Semi-deep energy retrofit results
I thought I would share our energy usage results from our semi-deep energy retrofit as we now have one year of usage to compare results.
Our home was a brick/block ranch built in 1960 with an main suite addition built by previous owners in 2005. We had 3 gas furnaces with heat pumps. Two of the furnaces has humidifier. We also have a gas range, 2 rinnai tankless water heaters, gas fireplace, and gas pool heater. Blower door test couldn’t pressurize fully but estimate was around 10ach. House was drafty and cold in the winter. Finished square footage is around 4,500′. Garages are under the kitchen. Located in zone 4a.
As part of a kitchen remodel we did extensive air sealing and insulation improvements where it was easily accessible or where the blower door indicates large leaks. We also clearly defined the garages as outside of the building envelope. This requires moving water lines to be up against the kitchen subfloor and insulating the garage ceiling.
We installed Fujitsu cold climate heat pumps 2 -9k, 1- 12k, and 1 -18k. Three are ducted and one in the kitchen / dining is ductless.
We also upgraded to an induction cooktop as well as electric ovens.
The results have been great. We used to setback the HVAC at night and didn’t heat the finished basement. Now we maintain the same temperature 24×7 in the whole house. The house heats much more evenly, humidity is great in the winter even without the humidifiers, and our gas usage has reduced by 67% while electric usage reduced 5%. ACH is around 4. We’ve also noticed the house is less dusty and we don’t have mice inside in the winter.
Thank you to everyone that helped guide us. We feel it was definitely a big improvement.
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Replies
Good work. I'm glad that you're enjoying other benefits than just lower utility bills, a tight house is quieter and cleaner too.
This caught my eye: "We also clearly defined the garages as outside of the building envelope." It always amazes me how many houses have issues with building envelope definition -- which is a fancy way of saying that the walls have hole in them. Or walls that aren't interior walls are insulated for some reason.
Again, good work.
mgensler,
Thanks for the update. It's always nice to hear the results of discussions we have here. I had a feeling your project would turn out well. You always asked intelligent questions, and seemed to know where you wanted to get.
Yeah, the garages were a pretty big project. In 1960 they just ran the sheet metal ductwork below the garage ceiling. It even had a supply vent for the garage. All of the copper water lines were then run perpendicular to and under the joists in the garage. Once we removed all the ductwork we knew we'd have to get all the waterlines up against the floor. We had to convert to pex to run through the joists. We ended up fixing a few structural issues with the drywall down including a joist pocket in the block that had a hole smashed in it to run pipes to the addition. This left the joist tail loose. We also reinforced some joists that were notched or had holes drilled too close to the edges.
Modern building code requires the garage to be a semi fireproof room, with no ductwork or other air pathways between the garage and the living space. It's good that you fixed those issues with your garage, since fire safety is important.
I've always liked doing insulation and air sealing projects on my own home because you can feel the results -- not just better efficiency, but better comfort. I think a lot of the time, people forget that you improve comfort too, since energy efficiency is probably most talked about. I know when I renovated my home office (that has a bay window that used to have pillows literally freeze to the wall with ice in the winter), it went from being cold in the winter to being comfy -- and it's in an outside corner of the house with two exterior walls.
Congrats on your project, I'm sure you'll really be appreciating your efforts as we head into winter this year!
Bill