Did we not have a summer, or was thermal bridging a huge issue at my house?

[EatenByLimestone]

Here’s my utility bill from July 2 through Aug 5th.

In March I had my house sided and 1/2” foam board was added to the outside under the siding. Nothing else was done to the house, except my storm doors were removed.

Notice the much higher electric bill last year. I must not have run my air conditioning much. I used 25% less electricity. Either thermal bridging (2x4 walls with dense packed cellulose in between) was a huge issue, or we didn’t have a summer. I distinctly remember sweating buckets outside, maybe it was just humid? The house color basicly stayed the same going from yellow to a creamy color so I don’t think it reflects more light.

Could I be overlooking something big?

 

[begreen]

Fixing thermal bridging and air sealing plus greater insulation make a difference.

 

[EatenByLimestone]

Oh, I realize that, I wasn’t expecting 1/2” of foam to make that much of a difference.

 

[begreen]

It's a nice improvement. Did they tape everything and seal around all doors and windows?

 

[EatenByLimestone]

I’m pretty sure they did not. I had done a lot of air sealing over past years from the inside already. He trimmed out the windows, but I don’t think he touched a caulk gun until the last couple days. When he trimmed them out he built out around the windows with 1x4, but I don’t think that would have made a huge difference.

 

[DuaeGuttae]

According to a website I like to use for degree day calculations, you have been having a summer at least through July.

Weather Data Depot: free downloads of heating & cooling degree days

www.weatherdatadepot.com

Insulation will certainly help. I noticed that your gas usage was also lower during that most recent cycle. Less laundry? Time away from home? Would the insulation have affected your gas usage in any way you can think of?

Can you tell that I’m actually quite curious about this? I also remember your lower bills after you changed your roof color. I remember showing your posts about it to my husband when we were picking shingles for our new house. We went with a light gray.

 

[EatenByLimestone]

If I remember right the roof made about a 10% change.

The gas is used for heating water, cooking, and the dryer. I don’t think…

Wait, we did go to Fargo for a wrestling tournament in July. That would have cut down on gas a bit. We would not have run the AC for that time also.

Let me pull up another old bill.

Looks like last August was extremely hot, or maybe it was wet and I had to deal with a wet basement.

Baseless excitement, lol.

 

[EatenByLimestone]

When the August bill comes in early next month I’ll see if the numbers are any different from last year.

 

[woodgeek]

A lot of AC is latent heat... energy to remove humidity. I'd bet the airsealing improved a lot with the taped foam.

 

[bogieb]

That foam will help keep wind, humidity and heat out before it ever hits a place that needs conditioned. I would bet it will have a pretty good impact on your winter heating also. Did you have your AC system tuned up (or recharged) in the spring? If so, do you do that every year or just every couple of years?

It would be better comparison to go back to the month after the siding was placed to get a feel for what went on.. Thanks to the jet stream, August wasn't as hot as last year in NH and we had most of our 90*+ days in July. I think we made a record for in a row days and average temp for month was way up. IIRC, NH only had 1 day at 90*+ in August - which was probably some sort of record in itself.

From my records you can see that June and August of 2023 were hotter/more humid than 2024. July was worse in 2024. Interestingly, heat/humidity did not necessarily track with how much sun we received going by the total solar produced each month.

 

[EatenByLimestone]

That’s quite a surplus you’re producing!

I’m still using window ACs. I really want to put a couple 1 ton mini splits in, one for upstairs and 1 for down, but it’s hard for me to prove I’d save any money doing it. It would improve comfort. I think that will be the deciding factor. My wife hates the noise of the AC.

 

[Pinesmoke]

The

That’s quite a surplus you’re producing!

I’m still using window ACs. I really want to put a couple 1 ton mini splits in, one for upstairs and 1 for down, but it’s hard for me to prove I’d save any money doing it. It would improve comfort. I think that will be the deciding factor. My wife hates the noise of the AC.

Minisplits will make her happy. I have one in my garage area I run mostly to dehumidify if I'm going to be out there working. I have to look up to see if it's doing its thing it's so quiet.

 

[EbS-P]

That’s quite a surplus you’re producing!

I’m still using window ACs. I really want to put a couple 1 ton mini splits in, one for upstairs and 1 for down, but it’s hard for me to prove I’d save any money doing it. It would improve comfort. I think that will be the deciding factor. My wife hates the noise of the AC.

You would probably save quite a few cold starts of the stove.

 

[bogieb]

That’s quite a surplus you’re producing!

I’m still using window ACs. I really want to put a couple 1 ton mini splits in, one for upstairs and 1 for down, but it’s hard for me to prove I’d save any money doing it. It would improve comfort. I think that will be the deciding factor. My wife hates the noise of the AC.

My solar system was sized to make about 30% over to account for the 4 months per year that it won't make enough plus I figured as I got older, that the mini split would be used more for heating as it gets more difficult to get the pellets up the stairs from the basement. Even after using the mini split last winter (because electricity was less expensive per BTU than pellets - even if I were paying for it). I still had a hefty amount left in March - which I elected not to take the payot and roll over (credits are good forever)

Changing to the mini split comment:
June 7, 2021 I had a 2 ton, 2 head mini split installed. I oversized the head units because of my experience with the struggles detailed below: 12k in my office to deal with the heat from all the electronics and 15k in the livingroom - oversized to deal with the massive heat from the south and west sun with dark siding. I'm glad I oversized for my circumstances, but oversizing is frowned upon as less efficient (so remember that looking at my numbers below.

Previously I had been using a 6k window unit (new in 2020 and energy star) in my office, which is small and air circulation is not a thing. It did not really keep me comfortable, but did help get rid of most of the heat from the electronics and I survived my first summer WFH. I used a 12k portable unit in my living room (which struggled mightily to keep it below 80* once the sun hit the SW and west side of the house. I also closed off the two bedrooms so in actuality between the two they were only cooling 600-650 sq/ft. Here are my comparisons of electricity use between summer 2020 & 2021. Oh yeah, and the indoor temp stays much more even:

 

[EatenByLimestone]

That did lower your bill down a bunch!