Hello from the great white north! Yellowknife NT to be exact!
not sure if this is the correct section i should post this or not, but ya never know till you take a stab at it!
Brace yourself, this is going to be long winded...
Just bought my first 'home' last fall (first time homeowner, long time renter), its an 1984 "alma" manufactured home. Its had some renovations over the years which includes the roof being re-done as well as the roof in the living room (center of the trailer) has been raised, but neither me or the previous owner know whats been done for insulation. the windows have all been replaced with triple pane lowE w/pvc frames as well as the exterior doors have been replaced with insulated metal and new screen doors. Overall a pretty tight and efficient setup for a 30 year old trailer.
Ive also got a wood fireplace in the living room, which is great because wood comes cheap, but its use is limited to outside temps in the low negative teens. even running the furnace circulating fan and living room temps over 30c, the end rooms struggle to make it to 20c and with any lower outside temps the bellybag starts to cool drastically (floors are f'n cold!), as does the crawlspace (uninsulated skirting). unfortunately, the sewer line from the bathroom runs outside of the bellybag, the full length of the trailer almost, till it hits the main. This line is insulated, but without the furnace being used, it cools off too much under there and the line will freeze eventually. (it needs some better support as it looks to be sagging in places and likely holds water or other goodies :? )
The current furnace is a 1992 nordyne M1GH090, and typical as always to a MH the furnace is a noisy SOB!
As per the usual, the 'normal' operating noise(air movement) of the furnace is a major nuisance as the furnace is located in the hall beside the living room.
I would like to do something about this noise pollution as well as move towards something more efficient.
J load calculation put me right around 26k/btu/hr (using a 60c temp rise) using guesstimate (worst case) values for the roof/wall insulation. using known values, my heat load is actually more like 17k/btu/hr ( average for a month of -20c to -25c outside temp).
ive also come to realize that the current furnace is a bit oversized. Currently its -35c (9km/h wind, -44c windchill) and with the t-stat set to 20c im seeing very consistent 10min/20min (50%)cycle times. even with outside temps dipping down to -40c (almost -60c with the windchill) i still wasnt seeing much more than 55-60% burner time and as much as the weather bites around here, we dont usually get more than a couple days a year where ambient temps are much lower than -40c (without the wind).
This average winter weather puts me around 800-1000L of propane per month (though only 600-800L is used for heating, i have other propane appliances) and at my current contract price of .65/L thats a bit over $400/month in heating
So... all this long winded crap aside...
I would like to do some upgrades over the following summer and im starting to put together a plan for this.
I would like to make the switch to a high eff furnace and keep it gas (propane, as to simplify the install and costs). ive been looking at the nordyne (miller/intertherm or whatever the heck else they want to call themselves these days) M7 series as they are as close to a "drop-in" replacement as a guy is going to get.
What im thinking, is an M7TL060A (possibly buy with a coil cabinet for future a/c because i hate the heat although it doesnt get overly hot here
). first stage should be more than sufficient to maintain a 20c inside temp during our coldest weather which should make it as efficient as its going to be while running the first stage, and the second stage should have no problem recovering heat loss from open doors/setback temps
My next an biggest concern of the project is the noise!
Ill make the assumption that the M7T is going to be a bit quieter than my current M1G (especially on first stage) but i would like to take it a step farther if at all possible. The biggest issue as usual is the noise at the return air (front panel). would their be much benefit in using a M7 with a top return air and ducting it through the adjacent bedroom closet and have it draw the return air from farther down the hall? (and installing a solid door infront of the furnace which is currently open). or would this make it slightly quieter in the living room, yet resonate and make it even worse for anyone in the bedrooms down that hallway?
Other plans for the summer would include insulating the skirting (R12 fiberglass w/vapor barrier) as well as inspecting the roofs insulation situation and maybe doing something there. Within the next few years the siding will have to be done, its got pretty old wood plank siding, i would like to do some R5 poly on the outside wall for a little extra wall insulation and likely do vinyl siding.
Crunching some numbers, making the switch to the M7T furnace alone should save me at least $70/mo in heating costs as well as some headaches from the noise! then the insulation is only going to compound the savings and hopefully with the crawlspace better insulated i will be able to set back the temps below 20c while i am away and save some heating costs there without having to worry about things freezing up.
So, my biggest concern is the noise, what are my best options for reducing the noise from the furnace and hopefully not just move the noise down the hallway. The ol lady wants to have kids in the near future and neither of us need a screamin banshee every time the furnace kicks in