Home Heating?

[Ted Robinson]

We just purchesed a new Silvercrest Home here in Oregon. It is 1385 sq. ft. with valted ceilings. Now we all know the weather here in Oregon is for the most part mild. But recently its been down to around 35 to 40.

My question is:

For that size of house.. what is the industry standard furnace size in BTU's for that sq. footage (1385)??

We keep our Temp set to about 70 and when the furnace comes on.. it runs for about 30 to 45 min.

This is just one of the things that people should consider when buying a home that (might) be in colder weather.

Any help would be appreciated.
Ted

[Ron Buckner]

Ted
As a sales rep I would probably opt to sell you no less then a 15KW (50,000btu) furnace for 1385 sq. ft. I looked at the"experts" answer and decided you might want an answer rather then a correct responce. He is right, but he's also skirting the issue. A 12kW furnave will keep you warm-slower.17Kw furnace will keep you warm-quicker, and noisier, along with possibly messng up your ductwork. The insulation standards of these homes is excellent, it requires much less heat to warm these homes then it ever has, but thats not really the problem. Any new home with a single t-stat control is going to have problems with uniform temperature control. We do not have sophisticated ductwork and air return systems in these homes and "climate control" amounts to nothing more then bath fans. By putting undersized furnaces in these homes the sound and air pressure problems can be somewhat controlled. To put in oversize units a whole set of problems can be introduced, why'll it is true they will run less, by creating additional stronger airflow, it holds they'll also create the corresponding chill factor that comes with it, so they will heat more quiclky, using more energy and require more still because of the stronger airflow. The answers to this problem lie in moving away from central heating in the first place. With our present insulation technology zonal heating has to be the way to go.

[Jon DeTora]

Ted:
The simple answer to your question is the following:
Minimal HUD regulations require a manufacured home to be constructed in such a fashion and to have a heating plant sufficient to maintain a 70 degree (F) interior temperature with an exterior temperature of zero degrees (F) in a 20 mph wind. Of course, HUD specifications can be improved upon by the regional government, an individual or by the manufacturer. In areas that suffer extreme weather a governmental regulatory body (such as a local building department) may require, through arrangements with HUD, more demanding construction/heating plant specifications in order to maintain appropriate interior temperatures, wind and snow loads.
With regard to the BTU rating of the heating plant: Given the size of your home I would expect the unit to have an 80,000 to 100,000 output. However, the actual output could vary and still meet minimal guidelines because satisfaction of the HUD (or local) specifications depends upon a formula that takes into account the rating of heating plant and other factors as: The size of building; floor, wall and roof R-ratings (the number that indicates the insulating quality of various material); type of exterior siding; thickness of insulation; type of window used; and the type of exterior doors used.
Accordingly, you could have a home built to energy efficient specs that would allow a smaller BTU heating plant to be installed. Likewise, a larger heating plant may be necessary if your home has few, if any, energy efficient technologies.
Take care. JDT.