One of the things that scares people about buying an old house is how do you make it energy efficient. And a quick observation when this house came on the market made it pretty obvious it was hard to heat. That's a big problem in Maine.
Adding dense pack cellulose in all the exterior walls |
You see, it had an oil tank in the basement. But it wasn’t being used anymore and the boiler had been switched to natural gas. But that must not have been enough to keep it warm (or it was still too cold, with unaffordable heating bills), so they added a pellet stove in the basement. Sections of the floor had been cut open to take that heat up to the first and second floor.
These floor grates give me a little vertigo every time I walk down the hall |
But that still must not have done the trick, because then they added a propane Rinai heater in the living room. There were also plastic accordion doors to keep the heat in from what I presume was a drafty foyer. And sadly, it was probably still very expensive to heat, because the only insulation was a few inches of fiberglass batts in the attic and around the sills in the basement. The walls were completely empty and there were spots where we could see daylight in the basement sills.
Obviously we need to change all that. We started with a blower door test, to see how leaky the house was. I've shared a lot of details about blower door tests in previous posts, so let's just say it failed miserably. This house is leaking heat all over the place.
The solution is 4-fold. 1) Air sealing 2) Insulation 3) Windows and 4) Heat pumps (which will also provide air conditioning – a bonus!).
The next step combines air sealing and insulation in the same step. We spray foamed the basement sills to completely air seal the sills, while insulating at the same time. Honestly, if you can only afford to do a couple of insulation projects in your home, this and adding attic insulation are the most important projects to do. This is especially true if you have hot water baseboard heat and your heat pipes run along the exterior walls. All that cold air that manages to sneak around the sills seriously degrades your heating efficiency. And by insulating 3 feet down from the ground, you’re sealing out the coldest part of your foundation (a basement floor is usually around 55 degrees, far warmer than what can be below zero at ground level here in Maine).
Next, we installed dense pack cellulose insulation in the walls. That means I get to keep all the plaster walls (I love plaster walls, they absorb heat from the steam radiators and radiate it back into the rooms for hours. And they give a house a whole different feel than drywall) and the beautiful original moldings that we have on the windows and doors.
Dense pack cellulose is made of shredded newspaper, so it’s a great environmental choice (spray foam is not great from that standpoint, so I try to minimize its use to where it’s really necessary). To install it in an existing wall, the guys cut a band around all the rooms, so the cellulose can be pumped into the entire cavity. Above and below windows, they drill holes to fill the spaces. It’s a messy business, but the guys did a great job.
As they finished each area, I followed up with an infrared camera to make sure they’d filled everything. In these images, purple means an area is cold. You can see behind the steam radiator there is a purple area, and we realized they had accidentally forgotten to fill that wall cavity, so they went back and filled it up.
Cellulose is also great for sound absorption, making for a much quieter house. For the kitchen walls (where we had gutted the walls), we used rockwool, which is also a great sound barrier.
The final step to insulation is the attic – it will be upgraded to R48 loose fill cellulose once the new ceilings have been installed.
3 – Windows
We are also installing new windows. Windows aren’t the biggest opportunity to improve energy efficiency, but these will be a nice change for the house. The existing windows are metal, incredibly heavy, and many of the glass seals have separated. The new windows will be much easier to use and as we install them we can fill the old weight pockets with insulation, which will also help keep the house warm.
And on a curb appeal note – we’re installing 2 over 2 (meaning two pane over two pane double hung windows), which is much more typical on a Second Empire (Mansard) home.
4 – Heat Pumps
Their slogan cracks me up - 'hotter than your Mom, cooler than your Dad' 😂 |
With the new insulation they will keep the house nice and warm and on the coldest of nights the steam radiators can still be used (some insurance companies won’t insure a home with just heat pumps). With all the added insulation, this house will be nice and toasty.
And the heat pumps can provide air conditioning in the summer - a real bonus! The wall units and exterior air compressors will get installed when the house is almost complete.
While we're talking about heat pumps, I should mention that we will also be installing a heat pump hot water heater. The boiler used to provide the hot water, which meant it had to run year round. This is a much more efficient approach and it has the added benefit of providing dehumidification to the basement.
You're probably wondering, how much does all this cost? And the answer is a lot. But this is the perfect opportunity to make these upgrades, while the house is open and accessible. And in Maine, we have rebates available through Efficiency Maine that help offset some of the costs. If you are renovating your own home, you can also apply for federal tax credits.
And the result will be totally worth it. Energy bills will be much lower, there will be a dramatic reduction in fossil fuel use and the house will be much more comfortable. I can't wait to try it out as the winter months approach!
I love all the info on adding environmentally friendly insulation upgrades! Thanks for sharing!!
ReplyDeleteThanks so much for reading this post! Typically they are the least popular ones I write - but it’s so important for the homeowner and the environment!
DeleteWe're fixing up a rambling, much-added-onto house that does not stay warm enough in winter and has a mish mash of abandoned heating solutions in the various decades of additions! It's nice to know it can be fixed. Also - how do you repair the plaster walls after the blown in insulation cuts??
ReplyDeleteYes! You absolutely can improve the energy efficiency of a drafty old house! The nice thing about cutting the band around the rooms for the blown in insulation is it's relatively easy to do a drywall patch in those areas and then skim coat them. Another option if you have vinyl siding is they can sometimes take sections of that off and pump in the insulation from the exterior.
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