Is goodman a decent brand of furnace. Also, how many BTU is necessary to heat 1500 sq ft house?

Aprox 60,000 BTU for a 90 plus or 75,000 BTU for a 80+ efficient in a moderate to cold climate. I've already beat up Goodman enough, you can search posts for what I think, but I'm truly tired of being so unkind to them. If it is all you can afford, go for it.

Goodman is just as good as any other piece of equiptment. It is a shame that many Goodman units get bad press because of bad instillations. Many cheap contractors buy Goodman because it is available to them and then install it wrong causing a problem. I have three Goodman./Janitrol units in rental homes for over 10 years and no problems here except to keep the filters clean and I had to replace the fan center on one unit.

I agree with the previous post on Goodman. Across the board I work on less Goodmans then the big name Carriers and Tranes. Could be more of those out there then the Goodman. But for the money Goodman has the BEST warranty out there. For like an extra $100 for a warranty they will cover up to 10 years of compressor replacement plus paying about $400 for labor, last I checked. As a comparison, last year we replaced about 26 Trane compressors. Same installers installing Goodman. 1 compressor failure for the Goodman. Those 2 projects were done within 6 months of each other and far less problems with the Goodmans. In my 14 years in this field I can best remember only having to change out or condeming less then 10 Goodman compressors. My opinion with Goodman is overall best buy up to 15 SEER. Anything more effiecient Trane or Carrier. Another plus for Goodman all parts are usually easy to find and most times much cheaper in price. As for the furnaces I think they also make one of the best 90% gas furnace out there. Again great warranties and not near as costly. Brian