I am new to this forum and impressed with the in-depth discussions. We are contemplating changing out our ageing A/C units, and would like to use the opportunity to address the entire HVAC system. We are unsure how long we will stay in this home…but will likely move within 5 years. Currently the HVAC system works well, but if outdoor A/C units can “look” old, these do. I am concerned they will fail and I will be forced to make a hasty decision instead of executing a well thought out plan. With respect to the radiant heat – we like it…a lot, but the propane bills are significant. My initial thought is to install a high efficiency air to air heat pump for 1st floor, and a new high efficiency A/C unit for 2nd floor. The heat pump would augment the radiant heat system in main living areas. I also thought about replacing the boiler heated domestic hot water system with an on demand hot water heater. Your suggestions are welcomed and appreciated. Here are the as is specifics: • Zip code is 27810 (Belhaven, NC) • Approximately 2100 square feet of living space • Two story custom house built in 1989 on 3.5 acres • Well and septic plus county water • Main living space including master bedroom on 1st floor • Three bedrooms (for guests), bath, and TV room on 2nd floor • Good insulation • All windows and doors are Anderson thermal • LP gas boiler/radiant baseboard heat – 3 zones, 1 on 2nd floor and 2 on 1st floor • Weil-McLain boiler series 3 (original equipment) • Amtrol indirect fired storage water heater sub to boiler (original equipment) • Amana A/C for 1st floor (original equipment I think) • Amana A/C for 2nd floor (original equipment I think)with air handler (installed in 2003) in attic

Amana's quality control in the 80's was very high. I toured the plant in 93 and saw how they went so far as to examine the copper tubing they purchased under a microscope to see that it met their standards.
I'm not suprised to hear your equipment lasted that long.

The problem you are facing is that the refrigerant they used is not going to be in a new unit as 1Jan10 R22 units were phased out. This means you are going to have to change end to end or do an expensive line flush.
So what your planning swiftly approaces 5 figures and easily exceeds it with an on demand water heater.

I think if you were my customer my advice would be to do nothing (other than throw $200 a month in a cookie jar).
Put out fires as they occur; if a compressor fails, replace the compressor or condenser (you can still get a new R22 condenser if it is shipped sans freon from the manufacturer).
When you sell the house in 5 years as you plan, their home inspector will say the stuff is old and needs to be replaced, so you give them an allowance off the price of the house and keep whatever you didn't spend in the cookie jar.

Their is little available that will offer you much of a return in 5 years.

Good Luck,
J

Joe Ami...really appreciate your input and words of wisdom...Keith

About the only thing that goes NPV+ in 5 years most of the time would be air-sealing & spot insulation if any gaps can be detected.

At current propane prices, reducing your air infiltration by 30-50% could add up to more in after-tax savings than the cost of doing it in your time frame. See if there aren't insulation contractors in your area who specialize in air-sealing. If it's a full basement with an uninsulated band joist, there is likely to be sub-5-year payback on a 1" flash-shot of closed cell foam to insulate & air-seal the band joist & foundation sill.

HVAC mechanicals are a full-lifecycle kind of deal- if it ain't broke, you're almost always crazy to replace it until it's actually toast. The price of propane would have to triple to get payback on high-efficiency air source heat pumps sufficient to replace the boiler in under 5 years.

If you do end up having to bite the bullet on the upstairs AC unit, the fact that the ducts & air handler are in the attic close to doubles the load seen by that system, and a much smaller (and quieter), R410A refrigerant mini-split might get you the comfort in the room (s) you use the most at an upfront cost not too different from the installed cost of a replacement compressor in the ducted system.

Thanks much Dana...we're going to "nurture" our current AC units and hope they continue to provide good service. Although our home seems to be pretty "tight"...I'm going to have someone do a whole house air leakage test...again, thanks for your input...Keith

The moving within 5 years is the kicker. There are a 1000 ways to improve the hvac system in your home. I tend to agree with Joe on this one. I would check the nameplate on outdoor units to verify type of refrigerant. R-22 units are available , but miss matching indoor coil with outdoor equipment is never a good idea. The rated SEER can only be achieved when components are matched properly. Keep your equipment operating as is and let the next homeowner take on the expense of the upgrade.

Posted By acwizard on 05 Jul 2011 08:43 PM 
but miss matching indoor coil with outdoor equipment is never a good idea. The rated SEER can only be achieved when components are matched properly.

I want to clarify this point. I would say mis-matching ACs and evaporators is never ideal. That is different than never a good idea.
Providing the system works (though one may not reach the rated efficiency), the efficiency still improves and if a compressor is required, condenser replacement does not cost too much more and the warranties are significantly better. The un saavy home inspector may also mistake the entire AC as new vs just the condenser.
Their are casess where existing evaporator may not work at all or where efficiency can plunge. One could get an evaporator as well and still dodge total system upgrade and lineset flush or replacement.
j

If you are considering new HVAC equipment, and are tightening up the home, you may also want to consider something that will improve the indoor air quality. Ventilation + filtration.