[ccdre]

Hot part of California, routinely exceeding 100F June-Sept
Current system, 3-Ton split, R22 with evap coil and furnace in the attic (2 story home), condenser unit outside in the side yard.


The r22 evap coil is leaking and not holding charge. Heating performance of the gas furnace is great during winter.

Should I replace current setup with a heat pump, ditching the gas furnace? My electric rates seem exorbitantly high (PG&E @ ~$0.61kWh).
Should I keep the furnace and just swap the coil and condenser?

Do I go with R32 system or a 454B system?

Cheers

[vreihen16]

An inverter heat pump will definitely save you electricity during cooling season, and your regional power monopoly may have grants/incentives to install it.

We have oil-fired baseboard hot water heat, and a ducted inverter heat pump for cooling. Not paying California utility rates, the outside temperature where the oil-fired boiler is cheaper to run than the heat pump is around 25 F. If you have rooftop solar electric panels, the heat pump operating cost may be much less.

If you can install an inverter heat pump coil into your existing system in place of the existing AC unit, then you have the option of using gas or electricity during heating season.

We had our oil boiler fail a few years ago, and it took over a month to have a replacement installed. There was thankfully no sub-zero arctic cold blast during that time, and we ran the heat pump to keep the house warm until the boiler was back online.....

[ccdre]

Thanks vreihen16. I didn't realize it was even an option to keep furnace with a heat pump coil. That could be the right move here.

Originally Posted by vreihen16

An inverter heat pump will definitely save you electricity during cooling season, and your regional power monopoly may have grants/incentives to install it.

We have oil-fired baseboard hot water heat, and a ducted inverter heat pump for cooling. Not paying California utility rates, the outside temperature where the oil-fired boiler is cheaper to run than the heat pump is around 25 F. If you have rooftop solar electric panels, the heat pump operating cost may be much less.

If you can install an inverter heat pump coil into your existing system in place of the existing AC unit, then you have the option of using gas or electricity during heating season.

We had our oil boiler fail a few years ago, and it took over a month to have a replacement installed. There was thankfully no sub-zero arctic cold blast during that time, and we ran the heat pump to keep the house warm until the boiler was back online.....

[vreihen16]

Originally Posted by ccdre

Thanks vreihen16. I didn't realize it was even an option to keep furnace with a heat pump coil. That could be the right move here.

I'm not positive that it is an option, just suggesting that you check it out as a possibility.....

[dreamingat30fps]

I don't know much about this being I've lived most of my life in hot places. However house in NC has both a gas furnace and a heat pump as far as I know. When it's cold out, but above X degrees, the thermostat automatically uses the heat pump. Once the temp drops below X degrees it switches to the gas furnace. It took me a while to figure out what it was doing.

[2000cs]

Start with insulation and caulking/sealing all air intrusion. A blower door test (sometimes utilities provide this for free) will show you how much of an issue you have. Once the building is tight and well insulated, the strain on your HVAC and the cost to run it both will come down.

If the unit is otherwise in good condition, look at the cost of just the evaporator coil or outside unit. A new unit is pretty expensive, even if you can reduce the tonnage after insulating the building. But at least compare the costs of those two options before deciding.

Finally, as a way to defer deciding, if the leak is small try a product like Stop Leak (for HVAC, not automotive). I had a geothermal unit with a condenser leak and it was going to be about $8k to replace it. Called a second guy and he said we could get a couple of more years out of the unit with Stop Leak, which he then put in at a total cost of around $100 (10+ years ago). That bought me two years to save some money for the big replacement and to wait for a deal on what I needed.

[Murf the Surf]

Don't forget that your gas fired furnace uses electricity to circulate the heat through your home. We live in a pretty cold part of the country and use heat pump/propane forced air. The heat pump runs at a much lower blower speed than when the gas burner is going. We get very hot humid summers and the heat pump does a good job keeping the house cool. Up front costs might be higher but we cut our gas usage in more than half with the heat pump. It operates to -12C at which point it switches to gas. He can be adjusted down to -20C cut off but at it is currently cheaper to go to the gas at -12C.

[RickFLM4]

How old is the current system?

[CBO]

I'm in the IE in socal so we regularly see 100 degree days as well. Last year we switched from a 4 ton split conventional HVAC to an electric heat pump and furnace also running at 4 tons. Electricity bill has largely stayed the same and we keep our house at 70 during the day and 67 at night. Had I known about this 5 years ago it would've been the first thing we did to our house.

Only down side (kind of) was the up front cost compared to a gas furnace and condenser. But, we got a pretty good tax break for the install at the end of the year.

[Frostynorth]

You can’t necessarily use any heat pump condenser with a traditional furnace. As modern heat pump condensers require a variable signal for efficient operation, with an electronic expansion valve installed.
This would require to be a matched system.

The refrigerant doesn’t really matter, if installed properly, you shouldn’t need any for a long time. They all get phased out eventually.
R32 is flammable, a sensor should be installed, but is a relatively new product so will be around for a long time.

[Pheonix]

My coworker (in San Jose area) is looking to replace his HVAC system with heat pump! The 1st quote came in at almost $21,000
Yes, electricity is very very expensive here but you will never get your money back from switching from Gas (for heating).
I think he is in similar situations as the OP and thinking just to replace the Condenser and Coils.

[ccdre]

Originally Posted by RickFLM4

How old is the current system?

25 years. The house was built in 1999/2000 and this is the original system.

[ccdre]

Originally Posted by Pheonix

My coworker (in San Jose area) is looking to replace his HVAC system with heat pump! The 1st quote came in at almost $21,000
Yes, electricity is very very expensive here but you will never get your money back from switching from Gas (for heating).
I think he is in similar situations as the OP and thinking just to replace the Condenser and Coils.

$21k is insane, I bet most of it is labor.

[The J-Man]

61 cents per kWh? WTF. Mine is 13.5 cents in CO. Are your natural gas rates high too? I love my Bosch heat pump system, but at 61 cents per kw, I would prefer gas.

[RickFLM4]

Originally Posted by ccdre

25 years. The house was built in 1999/2000 and this is the original system.

Well then personally I wouldn’t invest anything into that original system.

[Pheonix]

Originally Posted by ccdre

$21k is insane, I bet most of it is labor.

Yes, I think at least 60%-70% are labor! They included $3,500 to remove and dispose the old equipment

[Pheonix]

Originally Posted by The J-Man

61 cents per kWh? WTF. Mine is 13.5 cents in CO. Are your natural gas rates high too? I love my Bosch heat pump system, but at 61 cents per kw, I would prefer gas.

In SF Bay Area, Time of Use rates would be as high as $0.65/kWh! Not sure about tier rates but probably over $0.50.
Natural gas is about $3.0]/Therms! I think still much cheaper than running Electricity but they banned future installations of Natural Gas equipment and prices will definitely go up.