Boiler pipe insulation questions

SpencerB

Hi all,

Last year I moved into a house with this relatively new boiler system and after dealing with one winter of too-high gas bills, I dithered about insulation until the onset of this next winter. I've read a few posts on the topic already and feel relatively confident about my plan, which is to buy some nice 1" thick insulation from buyinsulationproductstore.com and get busy. But before I get started, I just wanted to gather opinions on how far I should go.

I've had different contractors and handymen tell me different things. One tells me I'm losing about 6 radiators worth of heat to the basement (he's right, as there's at least 150' of uninsulated pipe down here). But others have said, hey, heat rises and if you insulate fully, your floors will be cold and your heat pump water heater will have to go on electric mode more.

With that said, does it make sense for me to do sort of a partial job here? Specifically, to not insulate the return pipes, tees, 90s and to skip the complicated set of pipes above the boiler (and just below the living room)? I'm not lazy, setting up those little pvc 90s actually looks fun to me, but if I'm trying to strike the right balance between efficiency and warmth, what's the right approach? There are already a couple areas I think I'll have to skip, like where the pipe passes a beam as shown in the pics above. I'd also love tips on how to handle the metal support hangers also pictured.

Thanks!

Spencer

leonz

You to have a heat loss study done for your home if you have not had one done already before you do anything else and in then you can see where you are losing heat in the living space and then work on repairs and upgrades to doors, windows and attic insulation.

Mad Dog_2

I'd just insulate the steam mains. Just about every boiler or mechanical room I enter, that at one time had everything Insulated, is a mess with missing pieces where repairs were made. Insulation also masks leaks that can fester and do worse damage. Mad Dog

pecmsg

Agreed 1st Get as Blower Door test performed to find where you can tighten the envelope. That will save energy dollars.

Remember that a large part of the heat in the basement travels to the conditioned space so it's not lost.

You can order pipe insulation online. Concentrate on the straight runs, the ells and T's can be done later.

ethicalpaul

i think insulation is fine, I installed it myself on most of my main. But if your primary concern is the cost of heating, I think the ROI on installing it will be a disappointment.

I wouldn't worry about your heat pump water heater, I have one of those too. There will still be plenty of excess heat down there (from the boiler itself if nothing else—like mine yours is right next to your boiler) for it to avoid resistance heating (especially if you tell it to).

Going alone with the others, I'd make sure the sill plate area was well insulated and air sealed before I worried about the pipes

SpencerB

Thanks all, this was tremendously helpful. I'll get someone in to do a energy efficiency/blower door test for sure, but then likely proceed with some straight run insulation. I understand that the ROI may not be overwhelming, but for a couple hundred bucks and a couple hours work, I figure it can't hurt. And anyway, the energy loss / cost is part of the concern, but evenness is also a problem. The 1st floor by the thermostat may be 70 (which causes the boiler to shut off), but the basement might be 80 and the upstairs (where the baby sleeps) only 65. So with only the one thermostat in play, I'm hoping that the insulation will help level things out.

@ethicalpaul, with that said, can you talk more about the sill plate? Mine is an old balloon-framed house with a ton of gaps at the sill plate up the sides of the house. I've heard divergent opinions here between "the house needs to breathe" and "seal that up!" The few panels of cheap styrofoam installed by the previous owners seem to not help much. I'm sure this would come up during the assessment but I figure it helps to make myself smarter before they come in with suggestions.

Thanks,

Spencer

delcrossv

A 5 degree delta between floors is more of a balancing problem. But closing up gaps in the building envelope will save fuel.

If you want to basement cooler, insulating the straight runs makes sense (and will help steam get to the rads sooner).

pecmsg

With that large of a temperature swing the envelope sealing will help but the venting is the bigger problem. You need to a) slow the venting downstairs or b) increase the venting in the Babys room ………………………………or both.

Where is this house located?

ethicalpaul

I think your house will still breathe plenty well even if you prevent wind from blowing through the basement, that's what I did anyway 🙂

You do need makeup combustion air every time the boiler fires, but again, unless you go hog wild there will still be plenty of air gaps around. I have considered running a flex pipe from an old dryer vent I have to near my boiler so it pulls from there instead of pulling cold air in from throughout my house when my boiler causes a partial vacuum when it fires.

SpencerB

Ok great, thanks. Hopefully the energy assessment people will help me strike the right balance of getting air to the boiler but not letting too much heat escape. House is in Westchester County, NY

CKNJ

On my balloon construction 1900 house i insulated the supplies in the basement right up to the bottom of the floor. Insulated the dry return all the way back to the boiler as well. If you want everything to stay nice and neat, get the PVC insulation covers like I did. Don't have to worry about tearing the paper cover on the insulation with them installed. And they will match the elbow and 45 insulation too.

bburd

The old books and original instructions for installing steam heat show fully insulated steam carrying pipes. There is generally no need to insulate the condensate returns.

In modern times people tend to remove the old insulation because usually it contains asbestos, and then not replace it. The result is hot basements, high fuel bills and slow steam delivery to the rooms above.

Start with those complicated pipes just above the boiler. They will get fully hot on every cycle.

SpencerB

Awesome, thanks again, all. Any tips on handling those metal hangers? Right now my plan is just to put the seam of the insulation there, tear in the paper flap and tape up as best I can

delcrossv

Just notch around the drops.