Wednesday, May 1, 2024

Energy Efficiency at the Cottage

There were so many things we loved about living here, but its energy profile wasn't one of them.  I first got suspicious when we noticed that snow on the dormer roof melted faster than anywhere else.  I usually call this 'bleeding heat' - when the heat is escaping the building so fast, that it melts everything around it.

Sure enough, we discovered there is no insulation along the dormer edges - which also explains why edges of the first floor ceilings and 2nd floor bedrooms were cold in the winter.  When I used my FLIR infrared camera, the dark blue areas (along the uninsulated edge of the dormer) show how much colder it is than the rest of the room. 

Cold areas are Blue/Purple (doors and windows are always colder because glass is a terrible insulator)

There is also no insulation along the 'sills' - the area between the basement ceiling and the floor above.  This area is notoriously lacking in insulation in old homes and will be a focus as we do updates.

What else needs work?  While most of the windows are newer replacements, the exception is the basement.  The basement windows are VERY leaky (I taped them shut when we lived there, because on a windy day I could feel my hair blowing) and we are replacing them all.  And of course we added a few new windows in the kitchen.

With all of this as background, what did we do to improve the energy efficiency?  A LOT!  Let's go through all the updates.

Insulation:  We used closed cell spray foam insulation for all the tricky areas of the house.  Spray foam is controversial.  It has the highest R value per inch of any insulation available - but it's also bad for the environment and while it's being sprayed/cured, it's not healthy for the installation team (they need to wear special PPE to stay protected and we can't allow anyone onsite for 24 hours).  So I try to minimize the spray foam to the areas that absolutely have to have it.

Safety over fashion!!

First the guys sprayed all of those pesky dormers that had been leaking warm air for the last 80 years.  That should make a huge difference for the house.  

Next, they sprayed the sills - they reached these from above via the kitchen floor.

And they sprayed the other sill from below, in the basement.  We didn't open up all the basement ceilings, but we were able to reach the majority of the sills. 

The upstairs bathroom got a combination - spray foam on the tricky angles, dense pack cellulose on the walls and loose fill cellulose in the ceiling. 

We also spray foamed the tiny addition ceiling, to maximize the R value there.   And the walls were filled with dense pack cellulose.

For the walls, we used my favorite insulation - dense pack cellulose.  It's made of recycled paper, so it's environmentally friendly, but it also provides a fabulous sound barrier from the outside, helping the house be nice and quiet as well as fully insulated!  

Cellulose comes in huge bales that are fed into their machine and pumped through tubes to reach all the walls throughout the house

The house sounds so much different now!!! So quiet!!! 

And finally, we added insulation to the attic - bringing it up to the new Stretch Energy code standard - R-60.  That's a lot of insulation!!

R-60 = 18 inches of insulation 

Heating and Cooling:  So the good news - the house already had heat pumps when we bought it.  The not so good news, the heat pumps aren't powerful enough for a full Maine winter.  But they are pretty fabulous for 'shoulder season' - aka spring and fall.  And the air conditioning in the summer is pretty sweet!

Other bad news - the boiler is ancient.  We kept it alive while we were living there, but it's beyond its useful life.  So we had two options.  Go to all heat pumps (which meant ripping out the existing ones and replacing them) or update the boiler.  

It's so tiny compared to the old boiler!
We decided to update the boiler.  And yes, I'd like to get the house off of fossil fuels, but I also couldn't justify ripping out perfectly good heat pumps and spending almost twice as much to go all electric.  And there is the added complication that many insurance companies won't insure an all electric heated home.  

We updated with a newer, more efficient boiler.  It's also tiny compared to the old one!  And it allows us to keep the steam heat - which is sooooo nice in the winter (steam heat is my favorite!!  No dry, static air in the wintertime),  Those steam radiators heat up fast and also transfer the heat to the thick plaster walls.  That helps radiate the heat back into the rooms for a long time after the boiler stops running, making a super cozy home in the winter.

Updating the boiler required us to line the chimney with a new stainless steel liner.  We also discovered that the basement fireplace was exhausted through the same flue as the boiler - a huge code violation.  So that's been closed off and now we are fully compliant.

Hot Water: And last but not least, we needed a solution for hot water.  The old boiler provided hot water, but that meant the boiler ran all year long - creating an uncomfortably hot summer basement as well as lousy energy efficiency.  So we are installing a heat pump hot water heater.  They're incredibly efficient and also help provide dehumidification to the basement, a win-win!  

Moving Forward: We've passed all of our inspections and are ready to move forward with drywall.  With all of these updates, this house will be so much more energy efficient than when we started, ensuring a comfortable home with low utility bills.  


Pin It


  1. Do you ever use Roxul insulation?
    Also, I like how the slope of the roof on the little addition matches the slope of the stairwell ceiling.

    1. Thanks for noticing the angle! That was a key design element. 😁 And yes we do use Roxul when dense pack won’t work - for example it’s better in damp environments


Related Posts Plugin for WordPress, Blogger...