Given the Texas freeze we had 2 weeks ago, I think we should spend some time evaluating how we here in Texas design homes for the cold. The design requirements for cold weather here have been minimal. Say for example the building code requirements for slab insulation are light to non-existent for TX, based on the code. However, what does it mean when we say we should design for colder climates even in Texas?
To get this started, we want to know what is required first. I know my long term goal is to build remotely, outside of standardized building codes, but for this study I first opted to check what the building and energy code requires.
Based on the Energy Code, Texas has 4 climate zones 2a, 2b, 3a, 3b and 4b. This is due to the size of the state, reaching down to the Gulf of Mexico and having both moist and dry conditions. You can confirm that here, based on the 2015 Energy Code. As of this writing 2015 codes seem to still be the code most used in TX.
The lower number means it is warmer, the higher number is colder. So Texas can get as warm as US climate zone 2. On the opposite end, Maine and Minnesota go as cold as zone 7 (brrrr). It is important to note that this is totally different than the USDA climate zone.
Given the 2021 Texas freeze we had here, we had temps as low as 1 deg for us in the Dallas area, and I had folks that had -2 deg north of us in McKinney-about 10 miles north of us. In that 10 miles they often get colder temps and more chances of snow compared to us.
Looking at the climate zone map, does it make sense to assume a whole climate zone colder? Say, where I am now is zone 3A, should I go all in for zone 4?
In my opinion, this jump has huge impacts on cost and is honestly not practical. Your insulation and heating reqts skyrocket. Your contractors will be unfamiliar with what you are asking and will price much higher-even if just out of frustration. No, I don’t think the approach is to blanket-wise apply these colder requirements.
I am in no way aspiring for any government mandate or more codification, I am just using the current codes as reference. To that end I am using it as a larger lens to see what adjustments can be made to anticipate a colder climate in the future.
A more efficient approach might be, to check where vulnerabilities were seen in this Texas freeze, and review what solutions are standard to address these for colder climates. For example, how are plumbing pipes treated in climate zone 4? We saw a lot of piping damaged during the thaw here. This happened even in areas which did not have any power outages. Does it mean we insulate plumbing like we do for climate zone 4? Still, I don’t think we just grab those requirements and copy-paste them to our designs. However, I think it is prudent to look at these vulnerabilities in my future works so that I can avoid the exact same problems.
Instead of just increasing your insulation throughout, which parts of the home would benefit the most from a small increase in insulation? Your windows seem like a good option here, as the benefits work in normal summers and in extreme winters.
If climate does become more erratic, what kind of weather should you anticipate? It may be worth going for hail resistant roofing. Not only does your insurance rates go lower in normal times, but in extreme weather your home will have that extra layer of protection.
I wish I had a definitive list of TO-DOs, however this blog is not meant to give you a top ten things to do list. This blog is meant to aid in this process, this study to understand how we can make architecture more permaculture. How can we make homes more resilient in these changing times? Well, there is a big picture goal and there are the more tactical steps that we need to explore. These are some of those steps. A more comprehensive concept needs to be developed to better illustrate this and hopefully I can finish this sooner this year than I expect to.