performance building

A house needs to breathe ...

BY: CAROL EISENLOHR, BUILDING TOWARDS BETTER LLC AND HBA BUILDING SCIENCE CONSULTANT

BuildRight is coming up in April 2023 and we have an amazing event scheduled. In addition, we have invited Allison A. Bailes III, PhD to do a book signing of his newest Building Science book A House Needs to Breathe… Or Does It? An introduction to Building Science. Allison may not be able to join us due to a conflict with another conference in Seattle but if he can squeeze it in, he will. The book is an easy read, organized well, and uses language and details that make Building Science logical and easy to apply to building practices. I thought I would summarize one section in the book:

10 Ways to Make Your Home Comfortable

1. Comfort Begins with the Building Enclosure. When designing a new home, you have control over size, shape, orientation, and other factors relevant to comfort. Many people think comfort is solely the product of the heating and cooling system, but the architect has a huge influence on comfort.

2. Use Passive Strategies First. The comfort that comes from a properly insulated, airtight enclosure with wellthought-out windows has no operational costs associated with it. You pay for the comfort on your energy bills.

3. Make it Airtight. A house does not need to breathe! Airtightness solves a lot of problems associated with comfort.

4. Insulate Fully. Radiant temperature doesn’t get nearly as much attention as it deserves but has a huge effect on comfort.

5. Reduce Thermal Bridging. Insulation is great, but it is interrupted by wood which causes thermal bridging. Less is better when it comes to framing. Check out Advanced Framing alternatives to save money on lumber and create a more comfortable home for your clients.

6. Put the Right Amount of Window Area in the Right Places. Energy modeling can help you make decisions about window area, but it is best to keep the east and west window-to-wall ratios about 10% or less. You can go up to about 20% on the south windows and up to about 40% on the north facing windows.

7. Use Exterior Window Shading. Overhangs, exterior shades or trees can contribute to the overall comfort of the home by not letting the heat into the home. North facing windows do not need shading and south facing windows are easy to shade with a minimal overhang. East facing windows can take advantage of the sun in the early morning hours when the temperatures are lower but rooms with west facing windows quite often need higher air flow from the HVAC system to make those rooms comfortable.

8. Don’t Blow Air on People. One reason not to blow air on people is that the air they feel probably won’t be at room temperature. Heading air away from people allows it to mix with the air in the home, so by the time it reaches them, it won’t be as warm or cool as the air coming out at the vent. If the heat comes from a heat pump, it may occasionally blow cool air during the defrost cycle. Moving air isn’t comfortable during the cooler parts of the year. No one likes a draft.

9. Use Smaller Equipment Blowing Less Air. A high percentage of heating and cooling systems are oversized. The result is heating systems and air conditioners that come on for a short time and then go off, causing more noticeable changes in the indoor temperature. Consistency is comfort. If the system is grossly oversized the short cycling can shorten the life of your system.

10. Heat with lower-Temperature Air. Lower temperature air means more air flow to deliver the same

your BuildRight Coffee Chat with industry experts!

Join the HBA Building Science Consultant, ETO and other experts every Thursday at 9am via Teams or Zoom. Talk through code questions, address specific building challenges and find resources for better building practices. To schedule your individual chat, contact HBA’s Building Science Consultant Carol Eisenlohr at 503-710-2910 or buildingscience@hbapdx.org.

amount of heat. That helps even-out the temperature in a room, much like the air flow rates of right-sized equipment.

Hope to see you at BuildRight!

Remember: Design Right, Build Better!

The HBA Building Science Program is a technical resource available to HBA members free of charge, funded in part by Energy Trust of Oregon, Home Certified, OrePAC, Portland General Electric and NW Natural. If you would like to utilize the Building Science Program to create a continuous improvement plan focused on your building challenges or a plan to prepare for future code changes, contact Carol Eisenlohr, HBA’s Building Science Consultant at carole@hbapdx.org or call to schedule an appointment at 503-710-2910.