Heat pump

[goingtoarizona]

I live in Central California where the temperature ranges from 30F to 115F. My home is two story and the main AC/Heater unit is a remote style that's at least 20 years old. The upstairs unit has had the capacitors replaced several times and I think my service company is just patching a fault compressor.

When the original owner had the home converted from coolers, he was told that the main unit would cool the entire home. It didn't, so they added the unstaird Dualpack unit. I'd like to reduce my power bills ($500 a month in summer) and am considering a heat pump system.

I'm fairly certain that the HVAC companies in my area aren't up to date and will just want to sell me an easy-fix ac unit. Please chime in with your experience and the pros and cons of heat pumps so I can make an educated decision.

 

[ghnl]

We're in North Carolina. Our original HVAC for the house (1400 SF) was a propane furnace & A/C combined. When it needed repairs we instead decided to replace it with a heat pump with propane back up. Our average outside temps are in the 35F - 100F range. The propane back up is used when temps are below ~ 32F. Our electric bill increased by $20-$30/month and our propane use when down to almost nothing. (we still have a propane water heater).

I also installed a mini-split ductless heat unit in the garage & bonus room. It is not used everyday but it is nice to be able to push a button, eat breakfast and have the garage comfortably warm or cool. At that time none of the local HVAC companies had any experience with these units so their quotes for installation were astronomical - thus I did it myself - only paying for the final vacuum & connection (they came prefilled with refrigerant). I cannot see any significant increase in the electric bill from that heat pump.

 

[ant.foste]

I live in Central California where the temperature ranges from 30F to 115F. My home is two story and the main AC/Heater unit is a remote style that's at least 20 years old. The upstairs unit has had the capacitors replaced several times and I think my service company is just patching a fault compressor.

When the original owner had the home converted from coolers, he was told that the main unit would cool the entire home. It didn't, so they added the unstaird Dualpack unit. I'd like to reduce my power bills ($500 a month in summer) and am considering a heat pump system.

I'm fairly certain that the HVAC companies in my area aren't up to date and will just want to sell me an easy-fix ac unit. Please chime in with your experience and the pros and cons of heat pumps so I can make an educated decision.

A hea pump is nothing more that's a standard spilt air conditioner with the addition of a reversing valve and extra TXV which allows the unit to run has a heater when desired. You need to find the root cause of your units inability to keep up, which is driving your large electric bills.

 

[metlmunchr]

What type of heat do you currently have? Natural gas, propane, oil, etc. I assume its not electric or you'd be more concerned about the winter electric bill than the summer bill.

A heat pump is no more efficient than a straight air conditioner for cooling. Either one is available in various efficiency levels, dependent only on your budget.

The type of fuel available to you is the main determining factor in selecting the type of replacement system. For example, if you have natural gas, it will provide the cheapest heat most anywhere in the country unless you have dirt cheap electricity (not likely in CA) and a heat pump in the upper ranges of available efficiency.

OTOH, fuel oil or propane require a comparison of cost per btu for the fuel vs cost per btu for electricity to determine whether a fired heating system is a better choice versus a heat pump. Obviously, electricity is the only choice for cooling, so the only way to moderate that cost is via higher efficiency equipment.

Your 20 yr old unit likely has a SEER of 10. If you replace it with a unit having a SEER of 14, the new unit will do 40% more cooling for the same amount of electricity. A 16 SEER unit will do 60% more for the same amount of electricity as the 10 SEER unit.

The most efficient units today from most manufacturers have a 20 SEER. These units will do the same cooling as your current unit using half the electricity.

As you step up from a 14 SEER (the current minimum) to 16-18-20 SEER units, there is a significant price jump in equipment cost at each level. The higher the electric cost per kW-hr, the faster the payback and the easier it becomes to justify an upgrade to the higher efficiency systems.

As you might have figured out by now, there is no universal best answer to your question. If you provide the electric cost for your area and the types and prices of fuel available to you, it would be much easier to narrow down.

Re the capacitor replacements on your current units, capacitors don't play well with very hot weather. I was in the business for 20 years, and we always saw a marked increase in capacitor failures on equipment we serviced when temperatures hit about 95 degrees or more.

 

[yeldogt]

You need to get a room by room heat and cooling load done -- maybe an energy audit with a blower door test. The best bang for your buck will be insulation and sealing up any leaks -- plus you gain comfort.

Doing the proper calculations will tell you what you need to properly heat and cool the building. HP's don't help with cooling -- they can eliminate the need for a furnace in many areas because they work so well today. If you have any real long term heating load and NG is available -- that is still typically the best way to go. HP are great when oil and propane are the possibilities.

If you have wide cooling loads due to humidity and wide temp swings -- the new VS equipment is worth looking into.

What you don't want to do is just throw something in the building. Oversizing equipment is actually worse vs having slightly under... and using common factors that many guys use -- you get oversized

 

[finn]

Check with your utility company for available rebates.

Our electric provider participated in a rebate program that saved me $1500 on each of two mini splits if the seer was 22 or higher.