Beating the Cold by Building Smarter

Thankfully, in the Wilmington-Hampstead-Topsail-Wrightsville Beach-Leland region, we don’t have to deal with cold and snow quite like what is in the picture above. The temperatures do drop into the 30’s and occasionally 20’s from December to March, however, and it pays to be prepared.

What are the potential problems caused by cold temperatures?

• freezing, bursting pipes

• sweating windows

• sweating crawlspace (crawlspace moisture is never good)

• propane water heaters not firing due to cold propane (yes, this is a thing)

• HIGH ENERGY BILLS!

You may think that the buiding industry would have all these problems licked by now, but not so much. These are still perennial problems, even here in sunny North Carolina. We have a few best practices that we implement to alleviate these issues.

1. As often as we can, we like to build with minimum 2x6 exterior walls, versus the 2x4 walls that are industry-common. This allows any plumbing lines in the exterior walls to have a measure of insulation between them and the freezing exterior of the wall plane.

2. 2x6 walls means we can use 50% more insulation than a 2x4 wall. This is a big deal. We also prefer to use spray foam insulation or blown cellulose insulation rather than fiberglass batts. Fiberglass batts tend to bunch or sag in the wall, causing cold spots in the winter and hot spots in the summer, contributing to higher heating and cooling bills and lessening occupant comfort.

3. We avoid wood windows whenever possible, opting instead for vinyl or composite windows. Both vinyl and composite construction windows are sealed and weatherstripped tightly to prevent air and moisture leakage around the window itself, which helps to prevent sweating - moisture accumulation on the window.

4. Another contributing factor in the fight against window sweating is indoor humidity. High indoor humidity plus cold glass windows equals condensation. We like to control indoor humidity via the HVAC system. Oftentimes we can achieve proper indoor humidity levels by sizing the HVAC equipment properly, but best practice is to use an integrated whole-house dehumidifier. This is all done through return grilles and vents, so it looks no different than a normal HVAC system, but can keep the humidity levels consistent year long.

5. Crawlspaces are all too often bulit wrong; wrong meaning that the dirt floor of the crawlspace is lower than the dirt around the house, which means any water in the crawlspace is stuck there. I’ve often heard bitter jesting (you know, the kind where someone is lamenting a mistake they made) about having inadvertantly built an “indoor swimming pool under someone’s house” by not geting the grade worked out correctly from the get go. Don’t get me wrong, any builder can make this mistake, but it can also be remedied if not built properly. We like to prevent crawlspace moisture by getting the dirt level in the crawl space higher than the dirt outside, sealing the crawl space, providing a sump pump and drain just in case of flood (happens here occasionally), and by installing a dehumidifier in the crawl space to maintain proper moisture levels.

6. Propane gets denser the colder it gets, and this can make propane water heaters not ignite properly, which makes the water heater control panel alarm, and makes for very cold showers. It’s not pretty. The fix is super simple, but not common - insulate the gas piping. Problem solved.

7. How to combat high energy bills? This is a multi-faceted approach, and I won’t cover it all now - look for another blog post or series of posts on this subject, because the science and tech are always changing as we learn new things - but I will cover here how we fight against high heating costs. First we start with insulation - everyone insulates the walls (usually 2x4) and ceilings because building codes require this, but we go steps (leaps and bounds, really) beyond this. We insulate, first of all, the building slab with sheets of foamboard insulation underneath the concrete. This breaks the flow of thermal energy from the warm house into the cold ground during the cold months of winter (it is literally a huge heat sink, for all my mechanical engineering friends). We insulate and seal the walls (ours are usually at least 2x6) from bottom to top. We use high-quality, high density insulation that fills all the gaps and cracks, leaving no hot-spots or cold-spots. Best practice is to insulate the underside of the roof with spray foam insulation, but if budgets prohibit, then we will spray 16 plus inches of blown cellulose insulation on top of the ceiling. The next thing we do is use high quality double glazed, insulated windows, installed properly and sealed up tight with spray foam insulation. Every kneewall, bonus room wall, garage/house wall is insulated and sealed tightly. Our HVAC systems are highly energy efficient, as well as the water heaters we like to use. Each buliding is blower-door pressure tested to make sure there is no dramatic energy loss due to air leakage, and voila, in the end you have a building that beats the heating and cooling costs of the neighbors by 30-50%

Do you have a nightmare story about house or office issues due to cold weather? We’d love to hear more. Let’s start a conversation.