Kansas City MO · Member since 2014 · 357 posts · 349 votes
For those of you who have fully replaced old windows & installed new ones in your personal or rental properties I’m curious what percentage it reduced your utility bills.
I have an apartment unit that has 15 large old windows and has been getting high electric bills (electric furnace and no dishwasher or washer/dryer and temp set at 70) and I’m wondering if it’s worthwhile to replace the old windows. Curious the reduction in people’s bills after full window replacement on their older properties.
Rental Property Investor · Olympia, WA · Member since 2014 · 777 posts · 744 votes
7y
@Laura Williams This isn’t a yes or no answer. There are other considerations as well. I replaced 60 windows on a 1940’s Apartment. I wasn’t paying their power bill HOWEVER, the old windows got massive condensation on the inside which rotted out the window sills and walls below the windows - which I do pay for! Also I get better tenants now because the building looks and functions better.
Also I was able to refinance after my remodel (which include other items as well) and took cash out for my next deal.
I also have a duplex with older windows (1970’s). When I did a rent increase that was the #1 response, “Are we getting new windows for the increased rent?” I will eventually replace those just to upgrade the building. Again, better quality, better tenant, better rent.
Kansas City MO · Member since 2014 · 357 posts · 349 votes
7y
@Jim K. it’s an older house that was converted to a 5 plex built in 1930. It has a large basement with high ceilings ...one of the tenants was actually telling me he would be interested in making it an apartment down there and living in it so I’d say it’s a good size. The windows are typical small basement windows and the electric furnace for this problem unit is located in the basement.
Handyman · Pittsburgh, PA · Member since 2018 · 5k+ posts · 13k+ votes
7y
The age of the property was my next question, thanks.
I'm going to assume in the first of many assumptions that, with the heating problem you're discussing, this is a framed structure and not full masonry construction.
The wiring of the structure was most likely originally knob-and-tube. There's a quite reasonable chance that most of the visible basement wiring has been replaced with modern Romex/NM wiring, but there's probably still plenty of knob-and-tube left in the walls and between the floors. Clearly, there is no insulation between floors, and I would be pretty sure that a lot of the heat from the first floor is heading to the second floor, just as you surmise. Fixing that with insulation, if there is K&T wiring in the space between the floors, is likely not going to be cost-effective. You could add a drop ceiling to all the ceilings of the first-floor apartment to minimize the heat transfer between apartments -- if the ceiling in the basement is high in a 1930-era property I think it's safe to assume 8-foot ceilings throughout which would allow you to drop the ceiling up to six inches with acoustic tiles that also provide great ceiling insulation. You could also insulate behind those panels (no one ever does). That would not be an impossibly difficult DIY job if you ever get the first floor empty.
But...in a structure like that you're probably also losing a LOT of heat out of the basement/letting a lot of cold air into the building's thermal envelope through an uninsulated rim joist. Look that up and how to insulate a rim joist with polyisocyanurate foam and spray foam. The cold down there may be keeping the floors of the first-floor apartment cold, and if those floors are diagonal plank subfloors covered in thousands of pounds of oak tongue-and-groove flooring, as they would typically be in such a structure, that's a lot of thermal mass working against you to keep the first floor cold.
You can minimize that from the top by laying down rugs or even carpeting the whole space, but if you can work from below and insulate the cavities between the floor joists with faced fiberglass insulation batts, that should help more.
If you are willing to DIY that much insulation work, you can really change the math on the heat equation. My worry is that it probably wouldn't be cost-effective.
And of course, before you do anything at all, get a pair of educated eyes in there, an insulation contractor. My entire post here is based on hypotheses I've come up with a thousand miles off. I could easily be wildly wrong on this.
Investor · Kennedale, TX · Member since 2016 · 219 posts · 349 votes
7y
In my house we were paying $300 electric bills. We replaced our old drafty windows and spent around $6,000. Our electric bill went down about $50 a month. When we replaced our 30 year old a/c unit our bill went down another $100 a month.
At one of my rent houses the tenant was paying $300 a month for electric. The windows were in real good shape and the A/C unit was only 2 years old. They wanted me to put in more insulation. When I inspected the attic I could see places that had no insulation at all and other places where it was only a couple of inches deep. We added enough to bring it up to around 16" deep. The next month there electric bill dropped to around $150.
Your problem may not be as simple as just replacing the windows. Have you checked the A/C unit and insulation as well?
Columbus, OH · Member since 2018 · 20 posts · 6 votes
7y
@Alan Pederson
I haven’t done this yet, so take it with a grain of salt...I researched the R-values of new windows vs. old windows.... single pane=.9-1.5 or something vs double pane R value=3.5....sounds great right...
Well R value of normal blinds is practically nothing, whereas R-value of high end cell shade blinds can be as high as 5...blinds can as high as 150$ w/installation depending on the window and style obviously...I figure you can just put high end cell shades on all the windows and you’d be better off and out the door for cheaper than new windows...and it’s faster, looks better, and can be purchased in a neutral off white that acts as black out shades....
I’m new and looking forward to finding this out for myself... someone else probably knows more about this
Rental Property Investor · Portland OR · Member since 2018 · 2k+ posts · 3k+ votes
7y
Fwiw, i am living in a 1920s 4 plex right now, on the first floor with a walk in basement below me. They insulated the entire basement (which, btw is what i did in my farm house), and my hardwood floors are generally warm to walk on and it stays comfortable here and i generally try to keep my heat to 62ish. The insulation really helps.
Handyman · Pittsburgh, PA · Member since 2018 · 5k+ posts · 13k+ votes
7y
The "V" in HVAC refers to ventilation. If a residential building is not ventilated, CO2 builds up inside and oxygen is depleted. If the air inside a structure does not circulate, it smells musty. The vast majority of residential structures built today are still naturally ventilated through the stack effect. Warm air escapes the building through the roof, creating negative pressure inside the building and sucking in colder, denser air through the basement (special emphasis on the rim joist).
We understand the science behind this now. But in past decades, a lot of people believed that a lack of "fresh air" was the cause of many diseases. Even a hint of mustiness inside a building meant that you could get sick in it. So they made their buildings well-ventilated indeed. Gradually, science advances and showed that a lot of the diseases people believed were caused by a lack of "fresh air" were really caused by other things. Fuel costs rose, and builders started building residential structures with much less natural ventilation. By the 1970s, ventilation standards were so tight that "sick building syndrome" was created.
It's going to be functionally impossible to turn your 1930s-era five-plex into a sick building using modern insulation materials and methods. So that's why you should make sure the building loses as little hot air as possible through the roof and sucks in as little cold air as possible through the basement. You're interrupting the unnecessarily excessive stack effect that was designed into the building to naturally ventilate it.
Kingston, NY · Member since 2017 · 252 posts · 138 votes
7y
@Laura Williams
I would start with trying fill gap spray foam for doors and windows ( don’t forget that part !!!) . All you do with that is pull off the pieces of trim around the window and fill the gaps with the foam.
Kingston, NY · Member since 2017 · 252 posts · 138 votes
7y
@Dennis M.
I would get some spray foam labeled for doors and windows, remove the window trim, and fill gaps. ( it’s a softer foam than the stuff used in the walls)
This works wonders as there are often gaps in insulation where they had to cut it or shape it. ie around the windows and doors
NYC, NY · Member since 2016 · 617 posts · 456 votes
7y
If there's natural gas for the water heater, I would consider retrofitting to a gas heater.
There may be state or utility credits available.
As for the windows, if basically solid, I'd do the plastic window kit for this winter and look to insulate especially the window cavities and caulk when it gets warm.
Rental Property Investor · Greenwich, CT · Member since 2015 · 4k+ posts · 2k+ votes
7y
@Laura Williams, lots of great stuff in the comments already, but want to add a few more points.
1) Unless a window is broken or rotted, it almost never pays off to replace them. A much better option is to install storm windows.
2) As mentioned, your 1930s house is likely very drafty. Some local utility companies offer energy audits for little or no money. They’ll even do some air sealing, etc. for a nominal cost.
3) Airseal the attic as best you can, then add in as much cellulose insulation as you can. Air sealing is key though, that has to be done first.
4) Consider removing the resistance electric heat and installing mini-splits. They are way more efficient than resistance and provide A/C in the Summer, which is a selling point to tenants.
5) Insulate between the first and second floors. I believe the best solution without demolition is to: A) add 2" metal channels to existing ceiling. You can add RC clips for better results. B) add 2" mineral wool insulation between the metal strips.
C) Add a new 1/2" drywall ceiling.
I initially read about this method for sound proofing, here’s a very detailed study: http://www.mjm.qc.ca/publications/en/177881_Floor-CeilingAssemblies.pdf
6) A new method for air sealing an entire unit/home is AeroBarrier. Personally, I think this has the potential to be a game-changer. Check out this link: https://aerobarrier.net/how-aerobarrier-works/
7) Finally, I highly recommend checking out the Fine Homebuilding Podcast. That talk a lot about all of the topics discussed here and they are some of the top experts out there.
Investor · Morrisville, NC · Member since 2012 · 1k+ posts · 673 votes
7y
Lots of great information in this threat. I recently considered purchasing a MF built in the 1950s. When I saw the high electric bills, I wasn't sure how to estimate addressing the issue properly.
Trumbull, CT · Member since 2015 · 15 posts · 6 votes
7y
I might be cheaper to replace the furnace instead depending on how many windows. Your utility might offer a rebate for switching to gas, or for a more efficient furnace.
Investor · New Haven, CT · Member since 2012 · 285 posts · 175 votes
7y
@Laura Williams
Based on everything you’ve mentioned my first task would to verify that the elec is actually split between the first and second fl units. I’d imagine that the 1st fl is paying for some 2nd fl elec. it’s very common in older homes to not be isolated perfectly.
Kansas City MO · Member since 2014 · 357 posts · 349 votes
7y
@Shawn M. from talking to the electric company it appears the bills drastically drop in the summer ....which would make me think they aren’t paying for upstairs. I’m thinking something with the heating or HVAC is probably the makority of the problem. The electric company told me the highest past bill there was $630 which is just insane for a 2 bedroom apartment and higher than what the whole apartment rents for.
Investor · Seminole, FL · Member since 2016 · 94 posts · 41 votes
7y
@Laura Williams I would look at the efficiency of the heater unit. Sometimes clogged up filters restrict airflow and leave the unit running harder and longer than usual. Also when replacing air filters the higher quality ones keep out more dust but restrict airflow. I know it sounds backwards but the cheaper ones are actually better for your unit because air flows more freely through them.
Santa Rosa, CA · Member since 2017 · 325 posts · 701 votes
7y
One other thing you might consider. In my area the utility company will do a free energy assessment. I don’t know how extensive it is but considering the price it may be worth taking the afternoon to get an opinion. Sometime things like that are a waste but sometimes they can be quite helpful...it will be a coin flip
@Laura Williams, lots of great stuff in the comments already, but want to add a few more points.
1) Unless a window is broken or rotted, it almost never pays off to replace them. A much better option is to install storm windows.
2) As mentioned, your 1930s house is likely very drafty. Some local utility companies offer energy audits for little or no money. They’ll even do some air sealing, etc. for a nominal cost.
3) Airseal the attic as best you can, then add in as much cellulose insulation as you can. Air sealing is key though, that has to be done first.
4) Consider removing the resistance electric heat and installing mini-splits. They are way more efficient than resistance and provide A/C in the Summer, which is a selling point to tenants.
5) Insulate between the first and second floors. I believe the best solution without demolition is to: A) add 2" metal channels to existing ceiling. You can add RC clips for better results. B) add 2" mineral wool insulation between the metal strips.
6) A new method for air sealing an entire unit/home is AeroBarrier. Personally, I think this has the potential to be a game-changer. Check out this link: https://aerobarrier.net/how-aerobarrier-works/
7) Finally, I highly recommend checking out the Fine Homebuilding Podcast. That talk a lot about all of the topics discussed here and they are some of the top experts out there.
Good luck!
This.
Plus one more thing- airseal the box sills in the basement with spray foam. It's pretty easy but also doesn't cost much to hire an insulation contractor to do. The box sills along with #3 above will most likely be the most effective. But do get an energy audit (rebates might get you a great discount).
Minisplits are great, but cost a couple thousand, and work best for open floor plans. You'd need one head unit for each room. First insulate.
We insulated with cellulose between the first and second floors in our 1914 unit for noise. First floor tenants could hear everything going on in the second floor. Bonus is heat retention. We DID have knob and tube wiring to a couple of ceiling lights, and hired an electrician to remove those. With a 1930's house you might not have knob and tube. By the 30's wiring was starting to be BX cable (at least around here).
Handyman · Pittsburgh, PA · Member since 2018 · 5k+ posts · 13k+ votes
7y
New England and most of the East Coast stuck with knob and tube longer than the Midwest. I own houses in Pittsburgh built in the 1920s with rag wire, armored conduit, and K & T. The higher the initial quality of the house, the more likely it was built with K & T. But by all means check, especially if it went up in the late 30s (early 30s is extremely unusual -- Depression era).
Kansas City MO · Member since 2014 · 357 posts · 349 votes
7y
I want to thank everyone for all their feedback. This thread has taught me so much about energy conservation and so many great info and ideas. I had an HVAC guy come out today to look at the furnace and one of the 2 heaters on it wasn't working which he fixed. He thinks it will make a big difference on the bill as he said it had just been running constantly cause it only had one heater working on it. Apparently that is common thing to happen on an electric furnace which I just learned. I'm still going to take the suggestions on here to seal everything and the windows, doors and basement insulation and see what happens on the next bill...fingers crossed.