Specifically: would a 2-stage 3-ton condenser be more efficient than a 1-stage 2-ton condenser? Let's assume the same SEER rating for both.
What about reliability? – I heard that 2-stage are a lot more complicated, does it mean more maintenance?
Finally, is it worth the extra investment if we live in the NorthEast and will be using central air 2 months a year?
Please advise.
New Central Air Install: choosing single-stage vs dual-stage condensers
central-air
Related Topic
- Electrical – How to interpret a central air conditioner label
- Central Air duct does not blow
- Central Air and Hot Bedroom
- Length of insulated copper line set for a central air conditioner
- Relocate central air conditioners to roof
- Relocating central air conditioner coolant supply line
- Is the brand new central air conditioner short cycling
Best Answer
2 stage equipment is for comfort, not economy. You probably won't make that extra cost back if used 2 months a year and your house leaks AT ALL. (high SEER units are useless in an improperly insulated house) Reliability is doubled in that half the system can be broke and it will still work. Heating in your area is more important I would think, spend that money on an ECM (variable speed) furnace with a modulating gas valve. If they are the same SEER then there is no operating cost difference (right guys?). A 3 ton will just run less often and cost more to do so than a 2 ton. If you want to save money, thermal scan your house and fix those issues. Unless your rich and a green freak, I see no benefit to dual stage systems less than ~10 tons. The second stage is for those months that your first stage can't handle. In your situation it sounds like it would either always run both or never need the second.
ECM's pay for themselves in about 3 years, MGV's 10 or so depending on usage. 18 SEER will never pay for it self unless your house has an astronomical R value.
Quote from HVAC TALK
http://hvac-talk.com/vbb/showthread.php?178756-2-stage-furnace-not-more-efficient-than-1-stage/page2
This guy "Beenthere" seams to really know his stuff.