DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   HVAC (http://www.diychatroom.com/f17/)
-   -   Sizing New Carrier 58HDV Furnance (http://www.diychatroom.com/f17/sizing-new-carrier-58hdv-furnance-86686/)

PortlandGuy 11-14-2010 01:00 PM

Sizing New Carrier 58HDV Furnance
 
Home currently has a TempStar 80% efficient, 75000 BTUH input / 61000 BTUH output furnace that is about 15 years old.

Have been looking at the Carrier Performance Series two stage 58HDV models as a 95% efficient replacement (with the tax credits :) )

Have used HVAC-Calc to do a "Manual J" calculation and have come up with heat loss of about 48000 BTUH with my house on coldest (near record temp) at comfortable level.

So, here's my question.

One contractor is suggesting a 58HDV060 model (60000BTHU input / 58000 BTUH output (high) / 41000 BTUH output (low)).

But another contractor is suggesting a 58HDV080 model (80000 BTUH input / 77000 BTU output (high) / 54000 BTUH output (low)). This was a surprise to me.

In both cases, will install a Carrier Performance Edge 2-stage thermostat.

Which furnace is the correct choice for my application? I'm less familair with a two stage furnace. Thanks!

yuri 11-14-2010 01:04 PM

The first guy is right, you want to match the output as closely as possible. A little extra capacity over your calc is a good thing too. The other will be oversized for your ductwork and will overheat and have problems. Try get it installed with a genuine 2 stage thermostat and pay extra to run the additional wire for it if necessary. Relocate the tstat if pulling the wire is impossible/impractical and damages the wall/paint. Makes the unit a LOT more accurate/comfortable than the timed on stage switching you get with a standard tstat.


All times are GMT -5. The time now is 02:53 PM.