Oversized boiler, extremely high heating bills

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Dana

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A RESNET rater that does Manual-Js could get the load numbers right, but would only rarely be the right person to spec the mechanical systems or zoning, or the optimal order in which to do upgrades to the house & HVAC.

FWIW: Nate Adams uses a rule of thumb that the blower door cfm usually needs to be under 1 cfm per square foot of conditioned space before it's possible to fully control the comfort & moisture issues in a house. That isn't set in stone, but it's the right ball park. The location of the leaks make a pretty big difference. With 4400' of house and 6585cfm/50 leakage you have a way to go before hitting that magic 1:1 ratio, but at least you're not starting at 2:1 or higher.
 

JohnCT

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FWIW: Nate Adams uses a rule of thumb that the blower door cfm usually needs to be under 1 cfm per square foot of conditioned space before it's possible to fully control the comfort & moisture issues in a house.

Slightly off topic (although not entirely), but if a house is reasonably tight, does it make sense to arrange for outside air for an oil burner like a fan in a can?

John
 

Dana

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Slightly off topic (although not entirely), but if a house is reasonably tight, does it make sense to arrange for outside air for an oil burner like a fan in a can?

John

Pressurizing the room with blower driven air is excessive. In ultra-tight houses it's sometimes necessary to install a pressure-neutralizing duct for makeup air for the flue to draft correctly. In cold climates that ducted air would usually dampered with an AC duct zone damper and interlocked to the burner's ignition such that position of the makeup air damper is proven before firing. Leaving it un-dampered can create an unacceptably large parasitic stack effect heat load.
 

ilavey

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Realize it's been a long time since I last posted about this but wanted to give an update and see if I could get some advice.

This past summer a supply line to our toilet burst and ruined our ceiling in the basement. We've had to tear this out and so it seems like it might be the right time to fix some of the issues with our basement heating. Where we are currently at is we have a zone running to our air handler to heat the basement. The previous owners recommendation was to close all the vents upstairs and leave the basement ones open in order for this to work. I haven't found this to work well at all. The pressure is so high upstairs from doing this you can constantly hear a high pitch whistling noise from the air trying to get through the vents.

We'd like to panel radiators in the basement per a prior recommendation. I've talked with probably 10 HVAC companies in the area (Indianapolis) that just don't do anything with hydronic or refuse to provide visibility into how they do calculations into new zones.

As part of this, I've asked them about eventually replacing my boiler with a right sized boiler and they've almost all universally told me that you can't rightsize a boiler replacement to the heat load of the house, you have to do it based on existing baseboards (BTUs per linear foot). This doesn't seem to jive with what I've read in this thread or the resources I've been pointed to.

Am I misunderstanding my flexibility when putting in a new zone and boiler or do I need to continue my search to find someone in the area?
 

ilavey

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It's a Weil-McLain WGO-7 Gold Oil Boiler. My main concern in the immediate term is getting the correct sized zone installed in the basement.

It seems like someone not doing the work to properly size the new zone and then wanting to size the replacement boiler based on the linear feet of baseboard is a positive feedback loop.
 
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