Furnace replacement

[sudsmaster]

Seems that most home heating systems in this area are natural gas fueled, usually forced or passive air. Smaller older homes may rely upon passive floor or wall heaters.

The heating in this 1941 home is gas forced air. From the looks of the crawl space, it replaced an older passive air system. When I moved in, it was a lot noisier than it is now. The solution was to wrap the return duct - which runs about 30 feet under the house, with thick fiberglass insulation. My aim was to conserve energy, but a bonus was that it seemed to quiet everything down as well as eliminate some tin-can banging when the system cycled on and off. Also, insulating all the heating ductwork (it was mostly just with old asbestos tape wrapping) with 1" thick foil backed fiberglass insulation also helped conserve energy and keep things quiet.

The best energy conservation came from sealing off air leaks to the attic and great outdoors, and putting at least R30 insulation up there above the single floor ceiling. Before that the furnace was on almost all the time on cold winter nights. Afterwards, it's on for much less time, and insulating the return duct reduces that blast of cold air when it does cycle on.

The furnace is at least 30 years old. Can't remember the name; I think it's Republic but I'd have to find the manual that came with it. No way am I going down under the house to check!

 

[dustin92]

If you decide to go with forced air, go with the highest efficiency you can get/afford. We have a 25+ year old Amana 91% efficient and it vents through a pvc pipe.. Very little wasted heat. Also better to slightly undersize your a/c unit or the house may feel damp.

 

[mayguy]

100k BTU!? Wow, must be a very large house!!? Be SURE they do the Manual-J to get the correct size system.

We went from 115k down to 60k, and still kinda oversized for 50 year old 1,300 sq ft home when we were -30˚ a couple of weeks ago.

I have a 15 years old Trane Two stage furnace, and been the best heat comfort I've had in awhile, and paired up with a two stage stat. when it was -20's it ran steady in 1st stage the whole time .

I would perfer hot water heat but our house isn't set up with it.

 

[gusherb]

Good luck converting an old house to forced air. Unless you’ve gone through replacing every window, adding insulation and sealing every crack and crevice to the outside, you’ll probably end up regretting converting to forced air. ESPECIALLY if it’s oversized, you’ll be sweating and freezing all within the hour all day long.

 

[warmsecondrinse]

I'd stay with the hot water, but if that's not an option...

- FFS make sure the a/c unit is undersized!!! Newer units don't dehumidify as much as older ones. This is to get a higher EER. I can't handle heat & humidity and with window units I've always been comfortable with 1/2 to 2/3 of the the BTU's I supposedly need.

- Make sure the basement is included in the heated/cooled area with at least one return vent and one output. That will help keep the basement humidity down.

- If you have ducts running along the ceiling of the basement there's no need to insulate. "Waste" heat will warm the basement but more importantly the floor above so it's not actually wasted.

- Make sure you have a multi speed fan that lingers a good while after the furnace turns off; it reduces on & off cycling.

- Very important: Make sure you can manually turn the fan on so it can run continuously in both heat and cooling cycles AND WHEN THE SYSTEM IS OTHERWISE OFF.

- Make sure there's a return duct at the highest point in the house. This will help reduce temperature stratification during cooling season: First floor freezing second floor roasting

- Oversize your dehumdidifier in the basement and use it to dry out the air on high humidity days. You'll reduce your cooling load when temps are in the low 80's and you heating load on dank days in the 50's

That's all I can think of for now.

Jim

 

[retro-man]

All this talk of undersized a/c units. I have heard this for many years also. Well I did the opposite when I built my house 10 years ago. I oversized my a/c by 1 ton instead of 3 tons I went to 4 tons. I wanted to be sure my house would cool to whatever I wanted no matter how hot it gets outside. My findings have been my house stays very comfortable and my house is drier with the oversized units. Humidity stays in the mid to upper 30's and lower 40% humidity on the worst days. Better than any other house I have lived in with central a/c. It does not run as often or long run times. Also with bigger units you have bigger blowers which move more air quickly and removes moisture faster.

JOn

 

[wvkenmore]

Thanks for all the helpfull info. I knew I'd get some good answers here. The house is well insulated for its age and half Windows are replacement and the other one were completely ripped out and new construction windows. The basement is finished and is on 3 sides above grade (walkout). So I have 3 levels to heat.

Current boiler is 150,000 btu and only main floor was warm. I'm afraid the pipes are damaged from heat being off do to pump failure.

 

[norgeway]

Im old fashioned,,,hot water

heat is still the most comfortable, its clean because the hot air blows dust all over, this house has the baseboard in place but he took the oil boiler out years ago and hooked it up to a wood fired water stove, when he got physically unable to get wood, he installed a 90 plus propane furnace and Carrier ac, which works fine, but if I ever find a Iron Fireman vortex oil boiler it will be hooked up in my basement!

 

[sudsmaster]

Oh, forced air isn't that bad. Of course, if the home is already plumbed for hot water or steam heat, I'd stick with that. This here house was built in 1941, and from the looks of the crawl space it was either a single floor heater ion the living room/dining room area, or passive air through ductwork. The unit in there now was installed around 1980, and is 100,000 BTU. Of course it's an 80-85% efficient unit, being that old. I did insulate the attic, under most of the flooring, and seal off air leaks (like install an automatic damper in the kitchen range hood and make sure the bath vent fan dampers work). I didn't replace the 60's era windows (sliding horizontal aluminum, I know) but I observed the felt was worn thin so they would rattle in the wind, so I took them all apart and replaced the felt (really a sort of fuzzy strip). That seemed to help.

I researched the subject quite a bit, and while double pane windows are great, you have to consider that windows comprise a very small area of the total envelope. Far more important is reducing drafts, and attic insulation. For what remains, I have heavy curtains and/or window shades that help to reduce heat losses.

The home is 1650 sq ft, single story. You can tell when the 100,000 BTU furnace turns on and off, but it's not like a Baked Alaska. Actually fairly comfortable.