Furnace

[m Ransley]

What was the aproximate % efficiency of regular contractor grade furnaces in 1991. I do not know make or model.

[Joseph Meehan]

I believe it was about 80%

[steve]

80% at best.

[steve]

Talking about GAS right?? Oil could be lower than 80%

[~KJPRO~]

Normally, metal flu pipe and it would likely be 80% (Builder Grade)

If, and that's a big if, it has PVC flu, it would be around 90%+ (Premium Grade)

~kjpro~

[steve]

Speakin of..man..you GOT to see the new York concentric vent for the 90%+ units....freaking rocks..