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Are we serious about sustainability? #NZBS 11

As much as the buzzwords ‘sustainability’ and ‘green buildings’ are a part of our every day lives, we still fall short on the vast majority (almost all) of buildings. This opinion piece from Common Edge highlights how far we need to come as an industry: Why Architects Don’t Get It. To get where we need to be requires a fundamental shift in thinking for architects, engineers, contractors, developers and the general public. What we call ‘green building’ today is light years away from where we actually could be if we thought more consciously about our buildings.

The Bullitt Center project is one example of a building that aims to set the standard for sustainable building practices (Bullitt Center Case Study.) The Belmont (Belmont Case Study) is another that is moving in the right direction. Unfortunately, right now these buildings are the exception, a research project of sorts, when really they should be the industry standard. The gap between these buildings and minimal building code compliance is extreme. We can make better buildings, we’ve proven it, now it’s time to make this the new normal.

For construction professionals, it’s time to step up to the plate and move fearlessly towards creating buildings that embrace technology and advance the construction industry rather than cowering in the comfort of ‘the way we’ve always done it’. The technologies exist to make net zero buildings but it requires an industry ready to lead the world and the public to demand we do so.

So my appeal to the public is this: the construction industry can build far better buildings than we’re required to but this only makes sense if there is the demand. The industry isn’t going to change itself, it’s going to require everyone asking more of their design professionals, contractors and developers.

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Tertiary Education: An Acceptable Solution for High Rise Facades…

Is there a magic bullet that could be applied to every building facade to improve the chances of success?

The same way you consider the structure, the fire protection, the electrical, the mechanical and all the other parts of large buildings you have to consider the enclosure as it’s own discipline and it’s own system. If you’re constructing a small building, you probably would stick to acceptable solutions to design these systems (ie NZS 3604) and wouldn’t hire a specialist for each of these systems. But would you want to chose the structure for a 135m building from a book prepared by central government (with specialist input obviously)? Would you just assume the fire protection strategy you used on the 6-story apartment complex will work for the 150-unit aged care facility? Would you substitute professional knowledge for a checkbox?

Structural design hasn’t come up with the magic bullet that applies to every tall building without the input of a structural engineer nor will they probably ever come up with one. There are thousands of decisions, approaches, opinions, variables that go into a structural design that relegating structural design to a book is a recipe for disaster. Computer modelling has come a long way for structural design but these are tools to arm the craftsmen. Models only do what you tell them to, garbage in, garbage out. Powerful tools in the arms of the wrong people can lead to dangerous overconfidence in a design. Don’t misplace the advancements in computer technology for expertise.

In the same breath, there isn’t a magic bullet for facades that can cover every building to ever be conceived in New Zealand. Many products have made these claims but as many or more have failed along the way. Those failures were a misunderstanding of what the enclosure ought to do or is required to do and ignoring the relevant science about why they wouldn’t ever work. Now there is an underlying skepticism about any new product from overseas despite being able to apply science and engineering to determine beforehand if it’s going to work or not.

To move New Zealand forward on building enclosure technology and design, there is clearly a need for government investment. Pick a funding value, anything you think is the right number, now triple it, 10X?; the amount is inconsequential. The actual question here is where is that money best spent? There is probably some need for an enclosure design guide (if you are in a position to fund something like that, I’d be happy to contribute) much the same way there are structural design guides and standards, and other countries have some useful enclosure design guides (CMHC) but is that the starting point. You can build the boat, but you need a captain.

At present, there are less than 20 engineers (only about 8 of them actually live in New Zealand) with any sort of expertise in enclosure design on mid to high rise buildings. There are no university level programs in New Zealand that are training anyone despite the overwhelming demand. Many of these engineers are late in their career and there is no one to fill their shoes. No to mention all of them are working at capacity to keep up with the building boom leaving minimal time for ‘on the job training’.

Would an Acceptable Solution for buildings >10m be useful? or would the money spent developing that, to be used by so few, be better spent training young engineers how to design suitable robust enclosure systems for New Zealand climates. You could arm these engineers with the skill set needed to navigate a yet-to-be-named design guide or better yet, teach them the first principles behind building enclosure performance so they can make good decisions for themselves. That would arm the country with expertise to innovate, and construct better buildings than ever before. The benefit of that type of investment far outweigh the suitability of any design guide or acceptable solution.

The only long term Acceptable Solution for New Zealand enclosure design is university level training. Anything else is a short term solution.

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The Myth of Thermal Mass #NZBS 9

In Canada, in the 1970’s people started giving a crap about conserving energy in houses (it might be 2020’s before that catches on in NZ). At that time, and in the following decades, there were two competing ideas on how to do this best: Conserve as much heat as possible through super insulated air tight houses or the counter concept of passive solar heating, using the sun to heat the house and storing that heat in heavy things (‘superinsulated’ versus ‘mass and glass’). You can read many articles from people alive during those times (Building Science, Saskatchewan House), but to summarize decades of trial and error: the insulation option actually works (pretty damn well, and in any climate) and the passive solar thermal mass idea works almost none of the time (except a couple places with really nice weather, and only some of the time).

In fairness, both concepts have merit but you can do a good superinsulated house without the mass and solar part and you can do it anywhere in the world (it’s now called Passivhaus). But you can’t really do the passive solar thing without the insulation part and you need a really nice climate to begin with. Thermal mass is not the same as insulation; both are useful but for totally different reasons.

Insulation slows down heat transfer. The air (or blowing agent) inside the insulation is terrible at conducting heat so the heat on the inside of the house doesn’t cross the insulation. Funny enough, insulation doesn’t discriminate between summer and winter, so this insulation also keeps the hot summer days from coming into the house. That’s kind of what you want from a wall, to not be affected by what’s happening on the outside. You also need to think about the clear parts of the walls we call windows (NZBS6) but if you get the walls right you’re on the right track.

Thermal mass is different. Thermally massive elements conduct heat pretty well compared to insulation. 200mm of PUR insulation is about R-8, 200mm of concrete is R0.13. The difference is massive walls are thick. It takes a long time for the heat to get through the wall before you start losing it to the outside. This means they also take a long time to cool. This time delay is called thermal lag. The idea with thermal mass walls is the thermal lag balances out the hot and cold across a mean temperature somewhere in the middle. Great idea if it’s 24C during the day and 16C at night, you might balance out at 20 C all day. But if it’s a crispy 8C in Christchurch during the day and 2C overnight you’re not going to get the same effect. Aucklanders, you have periods of the winter in that same temperature range. The solar heat gain during the day in winter won’t make a dent in the temperature of a 200mm thick concrete wall at 4C. And if you turn the heater off at night, you’ll need hours and hours of heating to bring the walls back up to temperature.

For some reason, thermal mass is thought of in NZ as equivalent to insulation in many regards (probably because an energy model of one or 3 small houses said it was ok, so why wouldn’t it be for a 25-story apartment?). Per NZ 4218, you don’t have to insulate as much if you use massive walls (R2.0 vs R1.2 in Climate Zone 3). But this reduction comes with some huge caveats that are being ignored 1) this assumes there are other good elements of passive design included (ie. insulation, good glazing, orientation). 2) the mass has to be insulated on the outside and the mass exposed to the interior. If you miss those parts and insulate on the interior side of a large precast wall for instance, or put huge clear windows on the North elevation, you’re going to produce an uncomfortable, energy pig of a building. If you don’t want the insulation on the outside of your mass, then you can’t consider that wall a massive wall and R1.9 – R2.0 must be used on the interior side to meet the objectives of the building code (H1/AS1).

What does work pretty good is wrapping up your heavy wall in a blanket of insulation. The insulation protects the wall from the outside temperature variations so the heat and cooling loads on the heavy wall are reduced. Now the thermal lags peaks are not as dramatic and you could use this magical thermal mass reduction value and feel pretty comfortable year round. That’s the intent of that reduction, but I haven’t yet seen that wall built in NZ. Instead we see minimally internally insulated heavy walls being passed of a thermal mass walls to add precious square millimeters to 55 square meter apartments. But if no one is checking, why wouldn’t you?

The battle of mass vs insulation was fought in the 1970’s and 1980’s. Superinsulation emerged the victor but signs of the war still propagate through construction today. R-value reduction for thermal mass walls can only in the rarest of occasions be applied. Don’t believe the thermal mass hype, it only helps you if you already have a well externally insulated building. You can’t just rely on heavy things to keep you warm at night.

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Metal Roofs are a Sinking Ship (but we can…

Kiwi’s love metal roofs. And what’s not to love? Highly durable (50+ years), long track record, cheap, UV resistant, easily installed, many competent installers in New Zealand, and they are pretty OK at keeping out water (which seems like a good idea for a roof). Not to mention the occasional midnight wake-up when a heavy rain storm that transforms your roof into a 100 sqm snare drum! Never gets old.

That being said, this traditional roof has its roots and performance history in small, poorly insulated houses. These have been homes with massive amount of heat loss and air flow through the attic space, low exposure to wind pressure and relatively short lengths of metal. When extrapolating this assembly to taller, larger, newer buildings, metal roofs require some careful foresight and design to ensure they perform as well as their miniature predecessors.

This article isn’t to say that metal roofs haven’t done well on taller buildings, in fact the opposite, there are many around that are doing fine. If you dig into the science behind them though, they have worked mostly by accident, not on purpose. Adding in a little bit of building science black-magic to an already good roof assembly can make something even more robust. Maybe this is a bit of ‘if it ain’t broke don’t fix it’ (in which case stop reading now and get back up on the roof) or maybe it’s being proactive.

This assembly as installed in NZ, relies almost entirely on the continuity of the metal cladding, screws, and flashings. It starts by taking a continuous piece of metal (pretty waterproof) and putting hundred of screws through it (generally not a good waterproofing idea). Actually, we put more screws through metal when it has higher wind pressures so the more exposed the system is, the more holes we put through it. It’s kind of backwards but its been working or maybe more accurate to say it hasn’t been failing.

The underlay below the metal is mostly to collect condensation from the underside of the metal as a result of interior air and vapour migration and ambient dew and if you’re lucky it will stop rain water too. Most of these underlays absorb (read: not drain) water that is later dried out. This drying mechanism is critical to the performance of these roofs. The performance of the underlay is dependent on air flow from the space below, air flow under the metal cladding and the heat of the building below. If you have a really drafty, poorly insulated house, this assembly can keep up with leaks from the exterior and humidity from inside. So a lot of the shortcuts and detailing that worked in the past, no longer work as well. Dry it out faster than it comes in, kind of like bailing out a boat (thus the sinking ship analogy begins).

Imagine you intended to actually comply with the building code and made the ceiling air tight (to comply with H1 requirements) and added heaps on insulation (to comply with H1) but keep the same amount of exterior leakage and ambient condensation. The balance of wetting to drying on that underlay layer tips away from drying towards the wetting side. Enough to cause a problem? That depends on how much wetting and drying. Back to the sinking ship analogy, this is the equivalent of having a smaller bucket to bail out your boat.

The wind is also pretty critical to the performance of roofs, because there are pretty significant forces to resist. A home in New Zealand (less than 3 stories) might be designed for uplift forces up to 1.82kPa in the highest wind zones. Push that roof up 2 more floors (and use NZS 1170.2 calculation instead of NZS 3604), and those pressures double to more like 3.5kPa. That’s an order of magnitude different, like taking your dingy you usually sail Sunday afternoon around Hermes Bay suddenly to Tonga.

If you were to set sail to Tonga in your dingy, you would probably want to take some sort of reliable back-up flotation. Where as puttering around the bay, you might just have just a life jacket but sailing on the open water would probably warrant something more like an inflatable life raft. In a metal roof, this back-up is your underlayment. Loose laid underlayment might be OK for your bach on Waiheke, but for a multi-unit residential building, you need something more durable, taped seams and probably a rigid layer like plywood.

Including a plywood layer under your metal roof can take most of the air pressure differential away from your underlayment. It’s the only way to reliably design a roof at pressures beyond 3.3 kPa because there aren’t any underlayments in NZ tested beyond that (that I’ve found, if you have one message me immediately). Actually most underlayments are just approved for about half that at the 1.82 kPa range (NZS 3604 Very High). If you tape all the seams, and do a good job maintaining the drainage plane (ie, not blocking it with battens!) any rain getting through the metal gets effectively caught and drained (and/or dried) away. If you use a lower rated, untaped, unsupported underlayment, the wind pressure across the underlayment can open up the laps bringing in the rain with it and may also tear in a big wind storm. Plywood is the catamaran of the roofing world that stabilizes every thing but is generally just for the big boys.

In reality, the metal cladding takes a good portion of the wind pressure away from the underlayment but how much is anyone’s guess. That’s the sort of calculation you can only prove through years of testing on dozens of in-situ samples to come up with some sort of formula, design guide or rule of thumb. It’s probably also going to depend a lot on the geometry of the building, the parapet, the gap between the metal and the underlayment, the profile of the metal, the direction of the wind and 10-12 other factors I haven’t even considered. Could be 10% less, could be 90% less or anything or everything in between. All that suffice to say that designing for the full wind load across the underlayment is admittedly conservative but in the absence of any other information is appropriate.

Metal expands when it’s hot and shrinks when it’s cold. How much it shrinks depends on how hot and cold they get, what metal they are made from and how long they are. On a larger roof, like you’d have on a larger building, the lengths are larger meaning more movement. At 10m long you start to have to worry about the expansion and contraction of metal. Any total expansion greater than 10mm requires oversized holes with sealed washers to allow the metal to move around, where less than 10mm you can take up the movement in the tolerance of the fasteners and direct fix through into the purlins below. Something as simple as the colour of the metal can influence the expansion and thus the fixing pattern. If you chose a dark colour metal around 10m, you could get expansions around 11mm, where a light colour metal, wouldn’t get as hot, and may only move 8mm. If you’re still following the sailing analogies, longer ropes and sails stretch more than short ones.

Metal roofs for big buildings require more thought than what you are used to on houses especially new roofs with air barriers and insulation. It really starts with a kick-ass underlayment (your life raft) that let’s you get away with a lot. An underlayment that can take the full wind load would let you increase the ventilation below the metal making up for the air and thermal improvements below getting your bailing capacity back-up to compete with the extra rain and wind you’re getting on a taller buildings. Good chance, you’ve been sailing with just a life vest on and maybe you get away with it. But maybe on the next one, that life raft underlayment saves your life. Next stop, Tonga!

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Cyclone Cook vs NZS 1170.2 (NZ wind load standard)…

Cyclone Cook is exactly why I get up every morning.

If this “mid-latitude low” lives up to the hype, this type of storm is what engineers design building enclosures to withstand. This gives us a great chance to put NZS 1170.2 into some very real context.

For those of you who design buildings for a living, you should be familiar with the concept of serviceability limit states (SLS) and ultimate limit states (ULS). The SLS is a 1 in 25 year storm. Components are expected to require repairs but not experience catastrophic failure; bending, cracking, and leaking would all be permissible. A ULS event, is a 1 in 500 year storm at which complete failure would occur. These are roof tear-offs, cladding detachments, blown-out windows etc.

The 140 km/hr winds (39m/s) expected for Auckland today will exceed the SLS (~37m/s) for many buildings in the area but be less than the ULS (~45m/s) for most buildings. This means damage but not complete failure will occur to many buildings in Auckland today and tomorrow. This type of wind (with rain) exceeds the design standards for nearly every window in New Zealand (~>800 kPa) so you should expect your windows to leak today; there is nothing wrong with them, it’s just going to be more storm than they are designed to handle.

In other parts of the country in the direct path of Cyclone Cook, the outlook isn’t so good. Wind at 165 km/hr (46 m/s) start to approach or exceed the ULS of many buildings. Some detachment of cladding, roof tear offs, detached balustrades, blown over signs are all very real possibilities today in those areas, even for modern designed buildings. Stay safe, inside, and away from windows.

Combine wind at 39 m/s and 50 mm of rain per hour and you have a facade engineer’s dream storm, also known as AAMA 501.1 Testing. This is (supposed to be) the “perfect storm”.

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Sure window frame material matters, but so does geometry…

The models above show a really simple concept: window frames will conduct heat differently depending on both their material (obvious) and geometry (maybe not so obvious). All three of those models are aluminium frame windows with the same glass, same interior and exterior conditions, and same material. Drastically different temperature gradients and drastically different R-values due to just the differences in geometry.

In New Zealand, the thermal performance of windows in determined through NZS 4218 (kind of). This standard gives you a table to pick your window R-values. This method allows you to assume every aluminium window frame conducts heat exactly the same. R0.26 is the default value for a double glazed aluminium window in New Zealand. That is where the building code is set. Frame geometry need not be considered in this country, just the material and the glass.

Strangely, the same generic non-thermally broken aluminium windows with double pane glass are widely considered R0.17 in Canada. That’s because thermal modelling software, per NFRC, calculated that value (New Zealand theoretically also uses NFRC-100 for modelling, more on that below). Sail those same windows across the Pacific and apply far less sophisticated (and less accurate) methods and they become R0.26. Canadian building code requirements for windows left this technology behind 15 years ago…

Of course you could prove the actual R-value of your product in New Zealand using free software (THERM) and an experienced thermal modeller. NZS 4218 let’s you do this (if you’re that interested) and directs you to BRANZ “Standard Window R-value Calculation Procedure (SCP)” which then directs you to find a list of approved modellers from WANZ. Here’s the fun bit, there is no list! So you can’t follow the thermal modelling pathway to determine the effect your frame geometry has on the actual R-value of your product which leads the whole industry back towards mediocrity; gleefully thinking all aluminium windows are created equal.

You can’t generically combine an IGU with a frame and get a standard R-value, it’s just not the simple. The spacer bar, the position of the window in the opening (align with the insulation) and geometry can vary the actual performance by orders of magnitude.

WEERS is a new voluntary performance standard aimed at moving these generic R-values towards more realistic values. This is a shift towards more accurate performance numbers and is the first step towards getting better windows and homes in New Zealand. Unfortunately, I suspect modelling will show their windows are worse than than the building code so it’s hard to see voluntary adoption taking off any time soon.

Generic schedule tables are useful if they are granular enough to give you accurate results. Unfortunately, windows don’t fall into this category.

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Reclaimed Incandescent Heat #NZBS 5

We need to intelligently and purposefully consider the impacts of our design and consumer choices, not just follow the herd, latest trend, or excellent marketing.

Incandescent bulbs are inefficient sources of light; news to no one. About 90% of the power into that bulb gets released as heat rather than light. Try unscrewing a lightbulb that has been on for a while and the 1st degree burn on your thumb and index finger will confirm. New technologies use about 80% of the electricity that to get the same amount of light. Less energy for the same light output = energy efficiency high-fives all around.

But what about the 90% energy input that was being converted into heat energy? Funny enough, physics doesn’t discriminate on the source of heat. Be it from a heater, a furnace, a heat pump, your dog, laptop or a lightbulb, a kW of heat is a kW of heat. If you had 25 – 100W lightbulbs in your house chugging away at 10% efficiency, they are providing 2.250 kW as heat energy (90% at 100% efficient). That heat doesn’t just vanish, it’s still a very real, heat energy input that is useful in cold climate homes.

Let’s take a crazy idea and build a thermally efficient

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NZBC – Net Zero Building Code #NZBS 4

New Zealand Building Code (NZBC) is familiar to all in New Zealand, but what about another NZBC, a Net Zero Building Code; one world city is already on that path.

Costs too much, not feasible, impractical, not required. All the common arguments from those resistant to change when talking about zero emission buildings or Passive House. Despite the naysayers, there are countless buildings around the world, in all climates that use little or no energy from the grid, including office buildings, houses, and schools. Now one city is making it mandatory for everyone.

All buildings in Vancouver after 2030 need to be zero emission. Full stop. Every building. Read the bold plan here.

Could something like this work in Auckland? Of course! There are less heating degree days than Vancouver, more solar heating and a huge opportunity with the growing density in Auckland with the new unitary plan. Unfortunately, energy efficiency seems to be an afterthought in New Zealand at the moment.

Given the right voices in the right places, we can move our building code toward something that is competitive with the rest of the world. Oh, it really doesn’t cost more either…

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Warm Roof vs Cool Roofs #NZBS 3

For those of you unfamiliar with the concepts of warm and cool roofs, it has to do with the placement of the insulation layer. In a cool roof assembly (traditional NZ roof) the insulation is in the ceiling cavity or between the joists. As the insulation is below the structural deck (plywood, steel or concrete) the deck is on the cold side of the insulation and thus “cool” (see below for comments on how cool). In a warm roof assembly, you place a rigid insulation layer above the structural deck and then place the membrane over that. This keeps the structural deck “warm”. This assembly is also called a conventional or built up roof. A similar concept can also be applied to steep slope roofs, just think about where the insulation layer resides in relation to the sheathing layer and the same concepts apply.

The cool roof system has “worked” in New Zealand for decades mostly by accident. If you have minimal insulation in the ceiling, then the coolness of your roof is really not that cool as the heat from inside the house heats the attic space. This heat continually dries the roof assembly minimising any condensation and moisture build up. No roof sheathing and metal clad roofs both allow warm air to accidentally escape thus magically no condensation problems.

Some time in the past few decades, people in NZ decided that being warm in their house was a novel concept and they started adding insulation in the attic (walls too but topic for another article). While keeping people warmer on the inside, this also reduces the amount of heat that gets into the attic, creating a cooler roof (still not that cool). As insulation increases, sheathing temperatures continues to decrease to almost the same as outside temperature (lets say -10C in Queenstown). Now that air migrating into the attic space has a lovely cold surface to condense and causes some problems ( mold, rot etc.) Bear in mind that NZ does not have any exterior passive attic ventilation requirements like North America does (because condensation hasn’t been a problem in NZ yet…*foreshadowing*).

So with the continuing trend of higher insulated roofs (unlikely that is going to go the other way), and cooler and cooler sheathing temperatures, how do you build an assembly to get to R4-R6 (R22-R34) without causing massive systemic condensation problems?

One way is to first minimise air entry into the attic with an air tight ceiling. If air does get into the attic, let it escape through ridge vents and allow outside air to enter at the soffits. This is the defacto method in much of North America for a cool roof assembly, but this method may also not work that well in some climates. In addition, all the challenges that creating an air barrier in a ceiling presents, alternative methods are required.

Another option for highly insulated roofs is a warm roof assembly. In this assembly, the air barrier is created from above rather than at the ceiling level. There are naturally less penetrations through the roof sheathing than through the finished ceiling a modern home meaning an effective warm roof air barrier may actually be feasible. This assembly also has less thermal bridging meaning more insulating value per inch. The air barrier can be created either be sealing a plywood sheathing layer, a taped roof underlay or taped rigid insulation could all work depending on the circumstances. Great assembly if done correctly.

The key to any roof or wall assembly is to make an air tight layer and then insulate that air tight layer. I suspect we’ll be seeing a combination of mould problems and unique roof assemblies as the trend to higher performance houses continues. Ideally, we would get ahead of the curve and prevent the looming attic mould epidemic but I’m not holding my breath.

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Bring Your Own Heat #NZBS 2

If you read NZBS Ep1: Kiwi Windows or live in NZ you’ll note that most homes here don’t have central heating. For the purposes of this article, no homes have central heating (nor insulation but that’s for a future episode). The building code here specifically doesn’t require heating (again commentary for a future episode). No baseboard heaters, no furnaces, no thermostats. If you come to visit, pack extra socks.

1.0.2 The New Zealand Building Code does not specify minimum heating requirements except for old people’s homes and early childhood centres. Occupants will determine their own methods and levels of heating. Typically it is necessary and sufficient, for condensation control in winter, to keep interior temperatures 5°C to 7°C above exterior temperatures in a ventilated space.

No heaters, no energy use. Quite simple, if you don’t add any heat to the home you don’t have any to lose. The original net zero design. A home without heat in Canada is called a “shed” and is only suitable for occupancies by lawnmowers and snowblowers. Here it’s a place that people live. So do you need to heat a home in New Zealand?

Locals will say that New Zealand’s climate is mild enough that you don’t need heat most of the year. Overnight lows this time of year in Auckland are 5-10 C. Even for the huskiest of bearded Canadian’s that’s cold. Vancouver is the mildest climate in Canada (sounds like that’s probably true). Auckland is one of the mildest in New Zealand. The overnight lows in Vancouver and Auckland differ by a few degrees, hardly enough to justify not having heat through the night. And the rest of NZ is colder than Auckland.

So clearly the majority of people heat their homes in New Zealand. It’s just not a built-in feature or strict building code requirement. Instead of setting a thermostat that controls a purpose made heating system, you portage electric heaters around the house as you go. Despite some safety concerns about the types, sizes and temperatures of what ever heater the occupant has available or can afford, this approach probably has some energy saving benefits (just heating one room instead of a whole house). Although, the benefits are likely negated by the overheating rooms, heaters left on, inefficiencies etc. but there are some other really, really big problems with this approach.

Wood is allowed to get a little bit wet so long as it can dry out. If there is no heat source, it can’t dry. The leaky home crisis in NZ is still in full swing. Yes, face-sealed assembly and shoddy construction played a part but lack of heating didn’t help either. In fact central heating probably could have slowed the problem in many NZ homes and along the way helping solve another big NZ housing problem (that no one is talking about yet btw).

Leaving a room unheated means moisture in the air doesn’t dry out like it could otherwise. This moisture is retained in the materials and structure creating a breeding ground for fungus and mould. Once the mould and fungus are growing in their cold, wet environment, we enter this wet room and add heat to it to bring it up to between 15-25 degrees, exactly what mould and fungus need to flourish. If we had left the room at 20 C that moisture would dry out and wouldn’t be there to start the fungal growth in the first place. This predicament is manifesting itself across the nation.

NZ homes do have one common heating system, heated towel racks. In every bathroom I’ve been in thus far, there is a towel rack with electric heating. Not enough heat to warm a whole bathroom, but enough to dry out a wet towel before mold growth starts. Funny that concept, adding heat to dry something wet to prevent mould growth, might work with homes too…

Indoor temperatures below 16 C have been linked to increased respiratory illness. Many NZ homes struggle to stay above 16 C in the room they are heating not even considering the rooms that aren’t being heated. New Zealand asthma problems are at endemic numbers; 1 in 6 NZ people has asthma, it’s the 3rd leading cause of death in NZ. That’s an endemic. I’m trying to make the link obvious for everyone here: Cold houses = high rates of asthma. Seems like something worth looking into.

So here we are, freezing at the bottom of the world, clinging to portable plug-in heaters for 6 months of the year, with sky high asthma rates and rotting buildings. The NZ building code says occupants can figure it out themselves despite insurmountable evidence that we cannot. Auckland homes are some of the most expensive in the world, it seems that including a heater wouldn’t be too much to ask for.