Effect of replacing windows on heating

jeanc

I have an old home that is heat challenged. I have very old single pane steel windows. I'm trying to determine if replacing the windows will be worth it. It's a huge expense vs perhaps adding larger radiators. In the long term, new windows is a good investment. However, I'm really more interested in experiences of replacing them and hopefully retaining more heat in the house.

KC_Jones

I agree with hatteras on this one. Your money is typically better spent doing air sealing around the house and adding insulation. It is much better bang for the buck. All houses are different, but I ran the energy savings of replacing my windows (100+ year old single pane) versus just restoring them to be the best they can. The payback on my house was about 75 years or so....I will be dead before then.

jeanc

Honestly speaking, the leakage is horrible. At one point I taped up all the grids and after one winter of that it was too much work esp removing all the goo from the windows. Now I use heavy insulating curtains. But no doubt it's bad to the point of getting frost build up. I get the payback issue which is why I never did it. But i have to do something or like I said invest in bigger radiators or more baseboard which affects aesthetics.

ChrisJ

If you're going to blow money on something regardless,

Do the windows.

Don't put bigger radiators.

Paul48

If you were considering vinyl replacement windows, and are handy, you would kick yourself after watching them put in. The first might take you an hour, figuring out, how best to do it. The rest will take about 20 minutes each. You can get the sashes configured to look exactly like what you have. You can also get wooden replacement sashes. Either way, you insulate the weight pockets.

JUGHNE

You said you have STEEL windows....they may actually be aluminum. Maybe slider type operating sashes? With aluminum frames.
My daughter had similar aluminum windows. They were insulated glass which had lost their seal and fogged. The basic horizontal sliding concept of opening allowed more air leakage than double hung or casement crank outs.

The ROI discussion here has usually concerned wood frames and sashes.....and possibly with exterior wood storm windows.
New windows might not be much better than old wood windows that are not experiencing massive air leakage.
But if you have the metal frames, there is a lot of heat conduction thru the metal that wood would not have. You are probably aware of this as your frame frosts in addition to the glass panes.

How old is the house?

Adding more radiation will add more fuel usage (forever in the future) for sure but also more comfort.

jeanc

These are metal. Easy test.. magnet sticks. House is 90 years old. I would say the windows if not the originals must be 50 or 60 years old. I'm not sure when steel windows went out of style.

GreenGene

Just be careful, heat movement is measured in U and R numbers.

Window salespeople will try to sell you a triple pane super duper blah blah $$$$$$$$$$$, they are worthless.

When compared to single pane with storms or double pane the gain is very little for the money spent, you're biggest loss with windows is around the edge where it seals to the house or not, so XYZ company puts in triple windows and doesn't seal them properly for air leaks all around and you spent 40k for nothing.

GreenGene

U number is how much heat will move through a substance and you want a low number.

single pane runs @ 1.13
double @ .60 -.49
triple @ .35

so the money doesn't justify triple, good double panes are twice as efficient as single

GreenGene

The other thing to consider is the fact that since your windows are metal the frames themselves will conduct a ton of heat, it's what we call thermal loss or a thermal bridge, vinyl is a better choice, even the beams in your home conduct heat right from the sheetrock to the outside walls.

Fred

The old steel windows are absolutely the worst for leakage. If it were me, I'd spend the money on replacing them with good quality double pane windows. I wouldn't consider replacing them yourself as steel casement windows, unlike wood double hung windows don't have a frame or stops that are left in place so that the replacement window can be pushed up to the stops. They need to be properly installed and fastened. Being steel, and I assume casement windows, I have to assume your house is brick and sizing the windows is more critical as well.

Paul48

@Fred ..........is absolutely correct. I missed the whole metal windows thing. It is most likely outside the skillset of your average homeowner. You need construction experience, and the tools.

vaporvac

Before you even consider replacing them could you post some pics. If they are original, changing the style will significantly affect the aesthetics of your house with possibly little gain. A better route would be good exterior or interior storms. These can be used in conjunction with Peel 'n' Seal, a wonderful product that easy to apply with a caulk gun, and just as easy to remove. It can often last a couple of years and doesn't pull or yellow any paint it contacts. There are also other good methods to make a better seal, if that the problem.

hot_rod

If you decide to do the window upgrade, look into the various incentive programs. Energy Star goes until the end of 2016. Your state or local energy provider may have additional programs.

I would suggest using a pro also, sealing a replacement window to an existing building needs to be carefully done. It is not about the amount of silicone seal.


en

nicholas bonham-carter

No doubt your radiators were correctly sized for the windows when the house was built, so probably no need to add radiation. Is it steam or hot water? Maybe the system needs a bit of TLC.
Pictures of the Windows will help a lot.--NBC

Jamie Hall

I'll go with the crowd on this one! And it really doesn't matter whether they are casements or sliders -- those old post-way steel windows did a pretty good job at keeping the bugs out, and that was about it. I'd replace, however, with wood or wood clad in vinyl, double pane, and try to match the aesthetics as best I could (you can come pretty close).

Also, as has been said -- unless you are a good competent carpenter, this is not an easy do it yourself project, and it won't come cheap.

But this is one of the few situations where actually replacing the windows may even have a positive cost/benefit ratio.

Paul48

With some research, you may be able to find an early picture of the house, and do it justice by returning it to what it looked like before the metal windows.

Fred

Paul48 said:

With some research, you may be able to find an early picture of the house, and do it justice by returning it to what it looked like before the metal windows.

@Paul48 , I'm gonna bet this is a brick house, built in the 1940's and the steel casement windows are original to the house. There are earlier homes (especially 20's tudors) with steel casements but the hay day for them was in the 40's

BobC

There were some capes built just south of me in the 40's with steel casement windows. These were wood framed houses with clapboard or shingle siding - absolutely horrific windows.

There is nothing you can do to "fix" them. Anything else would be preferable.

Bob

JUGHNE

OP said house was 90 years old, that would fit with your 20's tudors.


Pictures would be really nice, what part of the country is the house located in?

4Johnpipe

We had crap windows and changed them 2 summers ago. Noticed savings on electric for AC right away and lower fuel bills by about 15% that winter.

ttekushan_3

Hi. I made gaskets for my Truscon steel windows (pre WWII) quite some years ago now. They still seal and operate beautifully. Then your heavy drapes do a great job at blocking the convection and radiant losses. Wind and snowflakes are a bit much to take. Gaskets are formed with ordinary silicone caulk and a breaker tape.

Of course, I stormed mine too. Night and day difference.
The gasketing job was maybe $20.00 in materials.

More here at last year's version:
http://forum.heatinghelp.com/discussion/154503/interior-storm-windows-anyone-have-experience-with-these-to-improve-heating-system

You'll have plenty of radiator for them.

jeanc

Amazing info. Thank you for the replies!
I had investigated storms (not homemade) but from a manufacturer who specializes in this. My grids are also leaky. (air comes in not only from the edges but the grids.) The windows are similar to this https://s-media-cache-ak0.pinimg.com/736x/6a/48/80/6a4880abbf141b4fa193fab70e8934d5.jpg

So the storm window folks said that all those grids need to be sealed. If air is leaking in and then hitting the storm, it will condense. That really means repairing the windows.

Seekircher windows specializing in restoring these windows but it's not cheap.

I had renewal by anderson come out. I would never go with them after getting too much marketing spiel and 'special' today-only discounts. Price is high. But my thought is, I'll be here at least another 30 years. Maybe worth it.

My hope is that the hot water system doesn't have to compensate so much and I can run it at lower temps rather than 160 most of the winter.

Appreciate the info on tax credits.

GW

I encourage you to invest in lowering heat loss vs adding heat output. The former will save you money forever, the latter will make you spend more forever.

Fred

@jeanc if that window is representative of the windows in your house, I'd be inclined to do whatever I could to save them. You won't get that kind of character from any replacement window and that style is important to the overall architecture and appearance of the home. Consider a good quality insider storm. Maybe even see if someone can custom fit a double pane'd insider for you, at a reasonable price.

jeanc

Thanks again. I do think windows is the way to go and will enhance the value of the house. When done well, I've seen many homes that don't lose character. No one wants bigger radiators.

But again... won't go with anderson. they call 3 times a day.

Next step after that is improve insulation .. I have practically nothing in my attic and with steep incline, I'm sure it's not helping.

Extremely humbled by the kindness and time put into responding. What a great community.

vaporvac

You clearly have a beautiful house of which you are now the steward. Things like this are never replaceable and replacements only look good until you learn to appreciate the difference. Then it's too late. An old house is a responsibility; repair the windows and get the storms. You needn't do this all at once, perhaps you can focus on the side that gets the wind most. @ttekushan did a wonderful job with his metal windows and I'm sure you can do the same. I have wooden windows and made interior storms that work well and give an R value that equals that of replacements.
Insulation in the attic and your basement rim joists is where you should start for the most bang for the buck. The difference will astound you.
Here are a couple of links for repairing/restoring old windows and insulating old windows.
http://www.oldhouseguy.com/windows/
http://www.oldhouseguy.com/interior-storm-windows/

The Steam Whisperer

I agree with restoring and upgrading the existing windows. Studies have been completed that place the average payback of replacement windows at about 42 years.....well beyond how long most replacement windows will last. The methods described here for weatherstripping and repairing steel casements are ones I have seen many times before. The comment about having to seal the existing windows before adding storms only applies to exterior storms. With interior storms, some leakage is desirable to help ventilate any moisture that builds up between the windows.
The wall of heat that is referred too by placement of radiators under windows appears to be a reality. Another steam expert and myself recently had an extensive discussion on this concept in reference to the extremely low fuel usage of many steam heated buildings with leaky single pane,steel framed windows. The particular building in question, a huge manufacturing facility converted to a artist gallery has a heat fuel usage only slightly higher than the most efficient specially constructed residential homes.

If there have been modifications to the radiator areas ( grills, covers etc.) it is probably advisable to remove them. It appears that wall of heat is highly effective for creating an insulating air space between the window and the interior, actually reducing the heat load of the building. This in turn will probably make the radiators large enough. In addition, if the system needs service i.e. balancing, steam trap replacements, this should be completed as it may reduce the radiation capacity. It is extremely unlikely that the radiators are actually too small, even with leaky windows. Most radiators from the 20s are 50% or more oversized for the heating needs.

Paul48

If those are his windows , where would you put the storms? Look at the picture.

vaporvac

@Paul48 , it is hard to see in the pic, but all the many old home I've been in have deep sills that would easily accommodate interior storms. These can be entirely or selectively removed in the Summer to open them. I've been in some old houses where screens were placed in the same interior space. Frankly, I hardly ever see any houses with open windows anymore and if Indiana is anything like Cincinnati, it's stinking hot and humid all Summer.
I don't have storms on all my windows and can verify @Steamhead 's comment. The wall of heat exists. @JeanC, I curious about your current heating system. Perhaps if you tell us a bit more, the pros here could suggest some improvements there. Often times rad covers severely impede heat flow, so a additional info.on that front would help.

Fred

@Paul48 , as Vaporvac has said, the storms would go on the inside and be removable in the spring/summer on any windows that the HO wants to open. I'm in Ohio too and Indiana's weather is very similar to ours. Opening windows most of the summer just doesn't happen much. I have even seen storms for casement windows where the storm is mounted right on the outside of the casement window itself, allowing the window to still be opened but blocking leakage from any of the grill/glass panes. Then the area around the edge of the casement is sealed with silicone or weatherstripping.

Paul48

I was looking at the device on the sill that holds the window open. It would make it very difficult to put a storm there. You certainly could mount it outside and make the window non-functional. Anything is possible, and where there's a will, there's a way.

vaporvac

I understand. It depends on the depth of the window. My BF has very similar windows and those storms fit on the inside. Of course, they can't be opened in the winter.

Fred

@vaporvac , that arm that holds the window open actually swings in to a parallel position, along the bottom edge of the window, when the window is closed. I think an inside storm would still work.

Jack

I've put in all new windows, not replacements in two houses. The first I went with a "value" vinyl frame window. 10 years later it was time to put in new windows. The current house I bit the bullet and used wood and clad Loewen windows. Excellent. The energy side has been well covered here but one thing that was a big benefit was the road noise reduction. It is amazing how the audio side of things contributes to your comfort.

JUGHNE

Just an unusual idea here....just call me crazy.

IF you have enough sill room on the inside of steel window.....you could remove all existing glass, then install custom made double hung windows in the openings. The exterior of the new window would be almost against existing steel frame work. some double hungs have screens and both sashes that can be removed from the inside.
The window could be trimed out with extension jams and casing to match your interior.

You get tight operable windows, with screens and the outside iron framework would retain the exterior look of the house.
Actually provide security.

Just a brainstorm.

SWEI

We replaced 150 steel windows in a hotel a few years back. The frame fins were embedded 3-4" deep in brick, so (after a LOT of measuring and planning) we plasma cut all the muntins, leaving about 3/4" of steel all the way around the building openings. New windows were sized to leave a 3/16" - 1/4" gap all around. Several thousand stainless Tek screws, half a pallet of window spray foam and nine weeks of trim work later the place looked great. These were commercial (Traco) aluminum windows with thermally broken frames and one inch Solarban 60 IGUs. The sound deadening was (is) truly impressive.

SWEI

The complete process had to be done from the inside due to proximity of other buildings in a downtown core and the depth of the building (100 feet from the street to the middle of the building, power lines blocking one side, major street on the other.) Exterior trim installed first, including new bottom flashings and stucco patching. The inside edge of the new window ends up in plane with the inside edge of the old steel frame. The foam was sprayed into the gap, partially filling the exterior trim, then the interior trim was installed. We went through three "expert" window companies before we decided to do it ourselves. It took 24 revisions of the M2O document before we signed off on the order.

SWEI

The exterior trim was cut to fit each window opening, a slot was cut into the exterior masonry (grinder and a diamond blade) and then the trim gets secured to the masonry using wood blocking (also custom cut per window.) The trim has a gasket which, when it's in exactly the right plane, seals to the new window.

The inside trim snaps into L-shaped aluminum clips, which were used to secure the windows to the frames. Despite their size and long history, Traco had never done anything quite like this before, so we had to develop the process and then have it blessed by the structural engineer, the architect, and the manufacturer's own engineers.

SWEI

The black(ish) metal protruding from the sill at the bottom right-hand portion of the detail is the old window fin. It should have been drawn deeper (down) embedded in the masonry.

The groove is only on the bottom, to secure the window and ensure complete waterproofing. You drop the bottom of the window exterior fin into the groove and then pivot the window into position. The top and sides look like this:

The wood is closer to 1x2, though they had to be ripped to fit the opening sizes. I think we ended up with seven or eight different thicknesses.

SWEI

We fabricated a bracket that used the old window fin as a guide for the grinder. The trim doesn't go as deep into the masonry as what was drawn, and there was a bit of stucco patching on most openings.

The extrusion with five connections is indeed a thermal break. I believe it's made from HDPE. Traco was short for Three Rivers Aluminum Company, an Alcoa brand, currently being marketed under the Kawneer name. They call it a NexGen Thermal Barrier -- quite impressive for an aluminum window.