Home energy audit vs. new windows
So I just got the results and suggestions from a home energy audit I had done a couple of weeks ago. For a little background, two story home with basement (and a partial crawlspace under a breakfast room addition), about 2100 sf, built in 2003, Climate Zone 4 (almost into 5, just about 10 miles south of PA border). As far as I can tell, original windows and standard production home. Not many comfort issues, but some areas are a little drafty, attic insulation was a little light (anywhere from 4 to 12 inches, mostly near the 12 inch mark).
So given the windows are fairly old, I have thought about replacing them. I have had condensation on the inside (actually in the room side) of one window, but it is also the window right outside the master bath, and the wife takes a bath every night and isn’t good about using the (substandard, per the energy audit) bath fan. Couple of other windows look like they have had some condensation in between the panes. Figured I would get a HEA and see what else (other than attic insulation…) might be beneficial to get done. Well, based on their recommendations, it is just under 5 figures worth of work, including seal all top plates and penetrations in attic, bring insulation level up to R-49, replace and re-route both 2nd floor bath fans (I think the existing fans are just routed to the soffits…), clean and Aeroseal the ducts (relatively poor air flow to second floor due most likely to oval ductwork to second floor), and seal off and insulate the walls of the ventilated crawlspace. All this would save me an estimated $237/year on my utility bill, so even after rebates it would still be a 30 year return on investment.
Now I know it isn’t just about saving money, but also increasing comfort, IAQ, etc., but I can’t afford to get both the HEA recommendations done and replace all the windows. Would any of the HEA recommendations provide more bang for the buck than replacing windows (none of which appear to be completely broken, drafty, etc. and therefore needing immediate replacement)? I had thought about a top down approach, i.e. do the bath fan and attic work and second floor windows now (9 windows, with the first floor work maybe next year. Not sure what direction to go as nothing is really “wrong”, but could be better.
Any advice/direction appreciated. Tried not to make the post too long, so if any more info is needed, feel free to ask.
Thank You,
Neil
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Not an expert - just a hobbyist.
I wouldn't be going out of my way to replace functioning windows that are only 20 years old. I assume they are all double pane? Are they aluminum, vinyl or fiberglass? Is your exterior trim and siding in good condition? Windows seem to be one area where innovation is happening quickly (European window technology moving over to America.) 10 years from now, attic insulation won't change much but I bet you will be able to get your hands on better windows than what is reasonably available today. When you do a window replacement, it's also a good chance to replace exterior trim so that's also another reason to wait until that work needs to be done. If you wait until you also need to do siding, you might decide to do a whole exterior retrofit with exterior insulation. I can't imagine you would justify that project in Climate Zone 4 today if your existing siding is in good shape (and it should be on a 20 year old building.)
Adding insulation in the attic seems like good bang for the buck and if you are going to do that, it makes sense to deal with sealing top plates and upgrading your bathroom fans before you blow in the new insulation. Once you blow in additional insulation, you won't want to do anything else up there. Tackling the attic may be the best option on this list.
Re the ducts. Cleaning the ducts is probably a good maintenance item regardless. I don't know if the Aeroseal is going to be worth it.
Re the crawlspace. I don't have a lot of knowledge about that. Is the current situation that your floor is insulated and your crawlspace is ventilated with uninsulated walls? I don't think you will want to just seal it off. If you decide to bring it into your envelope then you will need some airflow in and out of that space. I'd question whether it makes more sense to just improve the insulation under your floor if it is inadequate.
Would be interesting to know exactly what the issue is with the bathroom fans. E.g. could you get the upgrade you want by just dropping in a more powerful fan without having to re-route the duct. If don't need to fool around with ductwork and putting extra holes in the roof then you might consider simply blowing in a bunch of extra insulation. That's an easy job. Two folks show up with a truck with a blower and they are in and out in a few hours. Not as good as also sealing everything up but it's a lot cheaper because there isn't much work to it.
In my house, I had them blow in R30 (on top of existing) in about 600 sq ft of attic and blow in R22 (on top of existing) in about 400 sq ft of attic. They also installed some baffles to ensure airflow up from the soffits. The total cost before the utility rebate was less than $2000 Canadian.
Windows are vinyl, double hung. siding in good shape.
In regards to the bath fans, there is a very good chance that they are just routed to the soffits and not "up and out", hence both replacing and making sure they are venting out properly. The existing fans tested under 40 cfm.
The crawlspace current has a 1/2" wood hatch for access at the top of the basement wall (they basically cut a 2'x2' "notch" in the top of the concrete wall and screwed a hinged wood door there...). it has a concrete floor, is about 2'-3' tall inside, 2 supply HVAC lines (insulated) and batt insulation on the floor, and has vents on opposite sides. The HEA plan was to put a vapor barrier on the concrete, run it up the walls about 1', spray foam the walls from top plate down to the concrete floor, and put a vent in one of the supply runs as well as remove the hatch to the basement, essentially bringing it into the basement envelope (and remove the batt insulation from the ceiling/floor above). Insulation is thick, and actually not too saggy (the builder did 1x2 cross bracing across the bottoms of the joists, bot just the wire hangers...).
Aeroseal was a maybe, but someone else in my development had it done and went from 60% leakage to 10%, but I think she was in an older part (like late 80's or early 90's house) of the neighborhood.
Doing/making sure there were good baffles in the attic was included in the attic insulation/air sealing cost. Attic work (insulation and air sealing) is about $4k for 1200 sf of attic (which now that I look at it seems like more sf than I actually have up there....).
-Neil
Getting the bathroom fans right will be more critical if you improve the insulation in the attic and if there is a chance that they are throwing moisture into the attic. If they are poorly vented, then it's worth it to make that improvement. I had two poorly vented fans. One had no duct at all and I think the exhaust was crammed with insulation. I replaced that with the nice Panasonic fan and 6" insulated duct through the roof. The other had a duct but it just sat on top of the soffit which is no good. I put in a vent through the soffit that blows the exhaust out away from the building. Not as good as going through the roof but a meaningful improvement and there were some reasons why going through the roof was more than I could take on at that time. Here is a stock picture of a similar set-up (not my roof.) https://www.primexvents.com/wp-content/uploads/2014/12/plastic-soffit-vent-primex.jpg
If you walk around your house, you should be able to see if there are any fan vents above the bathrooms on the roof or if there are any vents through the soffits. If they are just venting into the attic then I would definitely deal with that.
For $4k, I'd hope there is a reasonable quantity of sealing to do. Did they mention if they would suck out all the existing insulation and start from scratch?
I have a hard time getting excited about the crawl space changes if they are going to cost a lot. Someone else may have a different opinion.
I also have a hard time getting excited about the new windows. Unless you spend a lot of money, I doubt you will see much of an improvement given that you already have double pane vinyl windows.
Have you considered installing nice blinds with electric motors that can be put on a timer? It may sound silly but high quality blinds on all your windows may be a better use of funds for saving energy. As an added bonus, it's something that will make your house look better and that you will actually be able to enjoy.
I am skeptical about the quality of the “energy audit” sound more a sales pitch to my ear.
Replacement windows almost never make economic sense. Even in new construction the upgrade cost of triple pain windows doesn’t make economic sense in zone 4.
If some of the windows have failed seals between the pains of glass getting the glass replaced generally not that expensive.
If your current attic insulation is say 10 inches of cellulose that would be R35 or so. It would be nice to get up to R49 or R60 but the amount of fuel to be saved buy this upgrade is very small and you are unlikely to ever recover the cost of this upgrade.
I don’t see what the problem is with the bath fans. They seem to work and are vented outside of the attic. The truth is most people don’t turn on the fan when showering and use it more for odor control.
I am a big fan of air sealing and blower door directed air sealing. The contractor measures how leaky the house is repairs some leaks and measures again over and over again.
Walta
@ walta100
Just to be clear, the auditor never suggested replacement windows (they actually suggested they were the pretty low on ROI in terms of energy savings and only suggested replacing if they were actually broken, leaky, etc.). They are all vinyl windows, not sure how easy to replace just panes of glass and reseal it.
In my attic, some areas are around 4 inches of insulation. Literally right down the center of the attic for about a 4' wide swath. I think that is where they were walking when originally blowing into the attic (there are still 2x4's across the joints to walk on) and then never covered that area up.
The fans don't appear to be vented out of the attic, maybe just to the soffits. And they do not pull hardly any air. I turn it on every shower, starting from when I start showering and leave it on for about another 10-20 minutes after I get out and the room is still very humid (and with the door open as well).
They did do a blower door test, which is directing the air sealing. Lots of air leakage at the top plates from what I saw as I was trialing around behind the auditor. Also had a mysterious amount of leakage around the 2nd floor hall bathroom toilet... not sure if that was being pulled up somehow from the basement or pulled down through the attic.
Per the report, my current tightness rating is 2182 (from 50 cfm). They are aiming for at least a documented and tested 20% reduction (to 1746).
Thank You,
Neil
Neil, your vinyl windows are very likely able to be reglazed. I have 40 year old vinyl Andersens and have had the glass replaced in a few of them. I simply popped the entire operable frame out ( a few screws, a few snaps) and brought them to my local glass place. A few hundred bucks later and I picked them up and reinstalled them. Easy peasy. I'm betting you could figure out how to get a frame removed.
If you can't find your where your bathroom fans vent to, that's never a good thing. Sounds to me they're venting into your attic, underneath your insulation, which is then restricting the exhaust and why they're not performing well. You need to locate the fan boxes in your attic ceiling and find where the exhaust is going. Rerouting to an outside wall is best.
It's very typical to have leaky top plates. You may have to bite the bullet if you really want to tighten up the house up there.
I am feeling better about your auditor.
Glass replacement is general handled by glass companies not window companies. It might seem like a minor difference but in reality, is window companies have no interest in repairing anything only in selling ten thousand replacements jobs.
It sounds like the last owners flatten some of the old insulation by walking and or storing stuff on it. Home depo will lend you the blower for free if you buy insulation from them. Sound like a cheap and easy fix since all the work is in the center.
If the way the fans are termitid was a big problem your symptoms would be delaminated plywood sheeting and mold in the attic. Not that the current situation is ideal just that it seem to be working well enough.
“I turn it on every shower, starting from when I start showering and leave it on for about another 10-20 minutes after I get out and the room is still very humid (and with the door open as well).” To my ear this quote sound pretty normal. Is there a mold problem in the bathroom? Do you see humidity reading over 55% in the heating season?
“Had a mysterious amount of leakage around the 2nd floor hall bathroom toilet” I would get in the attic and look for a vent pipe for that toilet and fill the gaps around that pipe with Great stuff caned foam.
The raw leakage numbers do not tell us much about how tight your home is or is not. Knowing your ACH50 number would give us something to talk about. If that did not make the ACH50 calculation for you this web could do it for you.
https://efficiencymatrix.com/air-leakage-unit-conversion/
Walta