2nd furance or zone system??

ranman469 · 12-25-2007, 12:06 PM

hi.
i have a 1959 bungalow in Dearborn Michigan. with basement and a 800sf second floor master bed room and bathroom.
the problem is it is hard to heat and cool the 2nd floor.
i`m debating between having the duct work re done for 3 zones basement,main and second floor and 1 furnace.
or just adding a second furnace and a/c for just the second floor, and what apx size?

there are allot of these types of homes in the mid west so i know i`m not the only one with this problem.
thanks for your input and suggestions.
randy

bigMikeB · 12-25-2007, 03:08 PM

Add the second furnace, residential duct zoning never works as good as commerical, you don't have the blower power or the space (bypass dampers/ etc) to really do it right in a house. VAV or VVT in a house setting is like trying to retrofit a VW bug with an Rolls Royce SST jet engine.

ranman469 · 12-25-2007, 03:11 PM

what btu and a/c apx. would be needed for 800-900sf?

bigMikeB · 12-25-2007, 03:13 PM

That isn't a guessing issue, you need to have a proper heat loss heat gain calculation done to match your construct/ insulation/etc.

ranman469 · 12-25-2007, 03:20 PM

i figured that. but everytime you call someone for a est.or info like this they want to sell you and stay all day until you buy. and i`m going to get and do my own work.

hvac122 · 12-26-2007, 08:19 AM

We do zoning in houses all the time with no problems at all. It has come a long way and is cheaper than two systems. We use Honeywell products but there are other good ones out there. The biggest thing is getting the duct and bypass sized right.

These are not jobs that I would try yourself. The sizing, design and installation are the most important things and if not done properly can lead to many problems.

bigMikeB · 12-26-2007, 12:43 PM

Quote:

Originally Posted by hvac122

We do zoning in houses all the time with no problems at all. It has come a long way and is cheaper than two systems. We use Honeywell products but there are other good ones out there. The biggest thing is getting the duct and bypass sized right.

These are not jobs that I would try yourself. The sizing, design and installation are the most important things and if not done properly can lead to many problems.

Professionally installed they work ok at best and never work as well as their commerical counterparts. You need minimum air flow through the dampers and a way other than a bypass damper to control air flow. I have seen some of the variable speed furnaces work better than most but it is just a cheap way to try and get real zoning.

hvac122 · 12-26-2007, 10:22 PM

Well I have had zoning in my house for ten years and it has worked perfectly. I believe that if done right there would be years of worrie free comfort. We have many out on variable speed blowers and have had great results. I will say that there are not alot of people out there that can do it right.