Should I get a 2 stage system?
Last Post 19 Mar 2009 09:31 PM by Alex_in_FL. 5 Replies.
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bartman99User is Offline
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16 Mar 2009 08:32 AM
Our contracotr is recomending a 2 stage system.  He feels that with the design parameters he has calculated, it will be in the 1st stage up to 2/3 of the time.  Of course there is an upcharge for getting the 2 stage system.  He calculates that somewhere in 1.5-3 years I will recover the cost of the added expense, though $$ is a bit tight for us right now. Other than cost (and assuming his calculations are all correct), are there any downsides to having a 2 stage system? 
BM
geo fanUser is Offline
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16 Mar 2009 03:44 PM

none that I can think of

better dehumidification

better eff

less start and stop wear and tear

more even temps

rgausmanUser is Online
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17 Mar 2009 12:34 AM
Hi BM,

What are your calculated heat and cooling loads? Your loads differences between heating/cooling will help in deciding ito go with either a single stage or two stage HP. Do you have a high solar gain? Do you like to use air conditioning all summer or open the windows and only use AC for July/August humid spells?

I am up here in Madison and I found my heating load was 38K and my cooling load was 24K and decided to use a 2 stage unit. This is my first full heating season and I am totally satisfied with the performance with my system. It runs most of the time in 1st stage except when I get down to design temp of 18*F then 2nd stage kicks in.

So what HP did you decide on installing? What ground loop system did you finally decided on? I know you were interest in standing column well.

Bob G.
http://welserver.com/WEL0058/

bartman99User is Offline
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17 Mar 2009 09:52 AM
Posted By rgausman on 03/17/2009 12:34 AM
Hi BM,

What are your calculated heat and cooling loads? Your loads differences between heating/cooling will help in deciding ito go with either a single stage or two stage HP. Do you have a high solar gain? Do you like to use air conditioning all summer or open the windows and only use AC for July/August humid spells?

I am up here in Madison and I found my heating load was 38K and my cooling load was 24K and decided to use a 2 stage unit. This is my first full heating season and I am totally satisfied with the performance with my system. It runs most of the time in 1st stage except when I get down to design temp of 18*F then 2nd stage kicks in.

So what HP did you decide on installing? What ground loop system did you finally decided on? I know you were interest in standing column well.

Bob G.
http://welserver.com/WEL0058/

Hi Bob,

Nice to hear from you again and it's great to hear that your system is working well.  We do get quite a lot of solar gain in the winter, so for our 2700sqft house (with a 900sqft conditioned basement) we are looking at 42k BTU heat and 48k cool.  We'll be going with a 4 ton GeoFurnace Manufacturing Inc. W-->W heat pump and will be using our well (SCW system) and a double walled heat exchanger.  Contractor claims  savings with 2 stage unit in winter and shoulder seasons and he is passing along his cost for the upgraded 2 stage unit.

We too will be doing a Welserver install, so when it is all up and running we should get a good handle on the efficiency.

Bart
joe.amiUser is Offline
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17 Mar 2009 08:41 PM
Pay back for a 2 stage is likely going to be decades in VA where I expect that heating and cooling loads are similar.
Comfort, dehumidification, longer warranties, R-410....all reasonable cases for 2 stage. Strictly monetary reasons....nope.
J
Just a Mechanic;
Geothermal; Savings Underfoot
Alex_in_FLUser is Offline
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19 Mar 2009 09:31 PM
Here in florida I would absolutely say go with 2 stage due to improved humidification control. However, I can't really speak for VA.

Generally the unit is more efficient on first stage than second stage. So you should save some money but the payback is unlikely to be super fast.
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