Gas fireplace for primary heat source?

I am wondering if anyone has information that can help on this one.
I inspected a 1,100 square foot single story home yesterday, built in 1905. The house was heated by only a 20K BTU, Heat N Glo, Vienna I, freestanding natural gas fireplace.
I am used to seeing these as supplemental to an electric heat source, and/ or just plain used as a decorative appliance. In this case I am not convinced that a 20K unit is sufficient to heat an old home, which has only R-30 in the attic, apppears to have nothing in the walls, and a partially insulated sub floor.
The home had electric baseboards that had been removed, and this happens to be the only source of heat left. I have been trying to locate information through the manufactuers’ website, and they don’t have a direct number to call. In fact they say to call a dealer if there are questions. My attempts to locate information from a local dealer have also been fruitless.

Does anyone know of any documentation, codes, or other standards that can be used to support or refute the conclusion that this stove is too small, or OK…besides the obvious statements I already made to the buyer inidcating that I am pretty sure it is undersized given the conditions.
I told the buyer I would attempt to help locate some information, both to help her, and to increase my knowledge base. She is also doing her own due diligence on the matter.

Any help is appreciated.

Not sure of the weather you get but I would not be surprised if it did not a bad job of heating the home . The biggest is getting the air moving but with a small fan it could be enough . A one story with a finished basement size about 1800 sq feey on each level home next to me they did the same thing
Size about 30,000 and they never turn them up to high and Have two heating the home well .
We do get some very cold weather down to 10 below F regullarly and some times colder .
I did a small home about 800 sq feet and the lady who bought it said she was is cosy last winter
Hope this helps Roy Cooke.

Look at IRC, R 303.8 “Required Heating”.

Ive seen and inspected many one and two bedroom homes here with a lot less than that for a furnace. Ive found homes with a small gas furnace (radiant heat) located in the hall to heat the entire house. When growing up it was not unusual to have only gas space heaters in a home. Check with your local authority about what the minimum requirements are.


Keep in mind that a furnace should be size to run almost continuously;y on the coldest day of the year. That means for the rest of the season it is over sized. So depending on how much the fireplace is used it could indeed keep the house warm for most of the winter. However, on a really cold day they may not be as comfortable or be using portable electric heater.

A heat loss calculation would be a more accurate determination of just how much they need.

As a side note; the fireplace is not nearly as efficient as furnaces available today.

So from a cost of energy and comfort level it would be advisable not to rely on the fireplace for the sole means of heat.

Paul Hinsperger
Hinsperger Inspection Services
Orangeville Ontario

Thanks for the IRC John.

It reads as follows;
R303.8 Required Heating. When the winter design temperature in Table R301.2(1) is below 60°F (16°C), every dwelling unit shall be provided with heating facilities capable of maintaining a minimum room temperature of 68°F (20°C) at a point 3 feet (914mm) above the floor and 2 feet (610mm) from exterior walls in all habitable rooms at the design temperature. The installation of one or more space heaters shall not be used to achieve compliance with this section.

I think the problem with the centrally located gas fireplace is it will have to be over 85 degrees F in the room it is placed, just to get 68 degrees F at the exterior walls of the bedrooms, etc.

This would have been a nice inspection for January and 35F degree weather. That would answer the question as to if it is acceptable. I am certain it is OK when it is 50F outside.

It definitely will not be as efficient as a furnace. Certain the buyer will be using supplemental space heaters.

Thanks for all the replies!