Tuesday, December 1, 2020

Can We Make a 1950's Ranch Home Energy Efficient?

Infrared camera photo after insulation
That's what we wanted to find out!  When we bought this house, the first thing I noticed was there was a lot less snow on the roof of the house than the garage.  Why?  Because it wasn't well insulated - too much of the heat was going up through the attic and melting the snow.  The garage isn't heated, so the snow doesn't melt, hence the difference between the two sections of roof.
See how much snow has melted off the poorly insulated roof on the right?

Obviously, we wanted to change that.  Energy efficiency is so critical to a quality renovation - and yet you seldom hear much about it.  When you watch an HGTV show, they talk all about the paint colors and countertops, but there's barely a mention of how they make a home better for the environment.  Do they even consider that?  Hmmmm......

So let me start with the end.  After all the work that we did, I had an energy audit done.  Why?  Two reasons.  1) In Maine, you're eligible for rebates from Efficiency Maine for work you do improving the energy efficiency of your home (and who doesn't want a rebate?), but they want an audit on the results.  Part of that audit includes a Blower Door Test (although it currently isn't required due to COVID precautious) 2) Because I really wanted to see measurable results of how well we did improving the energy efficiency of the house, I had the full audit done.   

The test is a giant fan inserted in the front door, that sucks the air out of the house, creating negative pressure.  From that, they can measure the air leakage in the house.  Current building code in Maine says that needs to be below 7 ACH50 (Air Changes per Hour at 50 Pascals).

Now sometimes houses are so leaky, they can't even get enough negative pressure to do the measurements.  We had done a lot of work, but I was pretty anxious to see how we did.  The result - 3.82 ACH50! Woo hoo - that's much better than the new house goal of 7 and will make a huge difference in heating costs for the future owners.  It also makes a huge difference for the environment.  

How did we get there?  There are a lot of considerations to keep in mind, particularly in our cold climate.  I tend to look at 3 different things: 1) Insulation 2) Air Sealing and 3) Heating System.  

Let's start with 1) Insulation.  I shared some of this story in a blog post a few months back (Insulation Update) But let's look at it in a little more detail.  Since we created cathedral ceilings in much of the house, we need to insulate them as a 'hot roof'.  That means the insulation goes directly against the underside of the sheathing on the roof.  It's the perfect application for closed cell spray foam insulation, which has the highest R value per inch you can find.  Typically R 6.0-7.0 per inch, it sprays on and foams up - with temperatures over 100 degrees (not fun on a hot day in a bunny suit - this poor guy was about 5 pounds lighter at the end of the day!).  It can't be sprayed too thick or it won't cure correctly, so it's done in a couple of phases.

You can see some of the benefits of spray foam in the photo below - see this infrared photo of the ceiling? (orange is warm, purple is cold)  See how nice and even - and orange - the ceiling is?  That's a nice insulation job. (the cross pieces are the antique beams we installed, which are orange because they're in the room.  The tops of the windows are purple, as well as some of the framing, because wood and glass don't provide insulation against the cold)

Basement starting point - no insulation behind the paneling! 
We also used spray foam in the basement - when we pulled the paneling off, we discovered bare concrete, so we insulated these walls as well.  And most importantly, we insulated the sills around the house.  This is the area between the top of the foundation and the bottom of the first floor (that dark space above the paneling in the before photo), which tends to be very drafty.  Since your heat pipes run along this area, it makes your heating system very inefficient.  When we spray foamed the sills in my own house, our heating bills dropped 10% overnight!
Look how nice and toasty those basement walls are now (BTW - windows are poor insulators, hence purple color)

Where else?  The crawl space that runs under part of the kitchen and laundry was never insulated, so we spray foamed those walls as well.  But even more critically, we installed a plastic moisture barrier over the old dirt in the crawl space.  Why?  Because as you tighten up a house, moisture becomes your enemy. It can lead to mold, decay and breathing problems.  And a dirt crawl space can be a huge source of moisture.  So heavy, 10 mil plastic goes down and gets foamed into the perimeter of the foundation to get a good, watertight seal.

In the original attic, the one you saw from the first photo with the melting snow, we used blown in cellulose.  This is an easy, cost effective insulation made of recycled newspapers.  It only has an R value around 3.2 per inch, so you need a lot of it!  But in that attic space, we had plenty of room to pile it up, with room for fresh air venting above.

New window installation
For the walls, we used a combination of spray foam, mineral wool and fiberglass, depending on its location.

And that brings us to 2) Air Sealing.  Just as important as insulation is air sealing.  It's pretty easy when you use spray foam, because it gets fills every little space.  But for the other parts of the house, we were pretty obsessive about sealing every air gap.  So every hole for electrical and plumbing got filled with foam.  We also added new windows (Low E/Argon filled), which were carefully installed with expanding foam around the perimeter to ensure a tight air seal.

Last but not least was the heating system.  The old boiler died 10 days after I bought the house - so it was clearly time for something new.  We had natural gas run to the house and installed a condensing gas boiler.  It's about the size of a suitcase and heats the entire house, plus provides hot water.  To my mind, it's a marvel of engineering.  It's the size of a suitcase and constantly monitors the desired room temperature vs. the outside temperature and the return temperature of the water flowing through the baseboards, to maximize the efficiency of the boiler.  It doesn't need a chimney, it has a direct vent thru the sidewall, as well as an air inlet for optimal combustion. And that results in 95.6% efficiency - pretty fabulous!  Our boiler was set up with 3 zones - one for the main living area, one for the bedrooms (because some people want the bedrooms a bit cooler) and one for the basement.   It doesn't make a lot of noise when it's running and provides nice, consistent heat from room to room.  Pretty great!
So that's our energy story.  As you can see, there's a lot of work involved in making a 1950's home energy efficient.  Insulation, air sealing and an efficient heating system are critical elements to creating a full system. And that effort is totally worth it - the new owners will enjoy the benefits for years to come!!

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