EVALUATION OF AN ENTRY-PRICED HEAT PUMP

See summary.docx: 23% reduction of gas+ electric bills; 83% reduction in GHG

LOCATION: 151 Borden Rd., Middletown, NJ (Climate Zone 4- near Zone 5)

OVERVIEW My house is Two story, ~3000+ sq feet, + partially finished basement. 1st floor and 2nd floor have independent centrally ducted 6 year old high efficiency Rheem HVAC. On Jan 6, 2022, I replaced a broken 1st floor exterior AC unit with a Rheem model 1436 (3 ton) heat pump ($4.9K, installed total). The HVAC vendor "Manfredi", Laurence Harbor, added one wire between the new heat pump and the existing furnace controller. I kept in place all other HVAC equipment. A central open core/stairs allows air flow between floors (3 months ago, I suspended a small booster fan to better equalize temps between 1st and 2nd floor.). Earlier, I measured the house temperature loses, during cold snaps, so I was able to calculate required heat pump size (This particular Rheem model was inexpensive (single speed) 3 tons was fine for winter, and provided steady heat down to 32 degrees for the entire house, and down to 22 degrees for just the 1st floor. (Installed performance was within 1-2 degrees of my calculations). When temps are below freezing day and night, I turn on 2nd floor furnace, to operate normally, thru its own thermostat.

DETAILS On Jan 6, 2022, The installer programmed my existing 1st floor Nest thermostat to turn on the automatic transfer from heat pump to my gas furnace, and showed me how to change the settings. The Nest is programmable to auto-switch to the backup heating source at any desire temperature (Nest uses WiFi to search for and download the current local air temp). I currently have it set to 22 degrees, where the Nest automatically turns off my heat pump and turns on the 1st floor gas furnace, which operates as it normally would, but auto switches back to heat pump when outside air temp rises above 22 degrees. (I set it once, and then forget about it). Turning on the 2nd floor furnace, below 32 degrees is the only manual thing I do. In a year or two, when tax credits and rebates flow in, I will probably get a "cold climate" heat pump for the 2nd floor. I will look for high heat output down to 5 degrees F and lower.

MANUFACTURER AND MODELS FOR FUTURE INSTALLATION See graph showing the highest heat output for several (they are multi-speed/variable heat - (and all are ACs) - the best (of this group) is the Mitsubishi PUZHA40 (+ PVAA30 indoor air handler). For reference, I note wholesale prices on top right. See how FLAT the output is down to 5 degrees. That would serve nicely for heat loss: my 2nd floor-dashed line from lower right to top left is one of my floors. The 5 degree crossover (small circle) is called the "balance point". At outdoor lower outdoor temps, my 2nd floor would slowly drop overnight, (the heat pump would continue producing heat). The next day my 2nd floor would recover as exterior temp rises.

Of course, Maine has much colder temps than NJ. The Maine state government had a trial with numerous homeowners. The backup was deliberately disconnected,and only the cold climate heat pump continued to operate at the lower temps. Results: most residents are not bothered by sleeping thru cold nights, and are happy with recovery the next day..

REFERENCES For over 500 heat pump and Building Electrification references see https://climate.smiller.org/REF/ The theme: heat pumps have numerous advantages.

Heat pumps can be a direct replacement by the same manufacturer of a broken exterior A/C unit, in a centrally ducted HVAC system. Heat pumps and A/Cs share very similar designs, except a heatpump has an internal reversing valve. The existing furnace can be relegated to a handful of days to handle extreme cold. Existing thermostats, such as NEST, can handle this upgrade. Maintenance is same as a standard HVAC (primarily regular air filter replacements).

ANALYSIS OF RESULTS: Heat pump energy efficiency is exceptional: In my house, my single heat pump consumes 5 Mega Watt hours/year of clean, renewable electricity replacing the heat output of the annual joint 25 Mega Watt hours (equivalent) gas burning of two furnaces, and prevents emissions of 5.6 tons of climate warming Green House Gas. New heat pump installations now benefit from rebates fronm NJ utilities, and federal tax credits. In addition, LMI families will beneift from NJ rebates in 2025 from the IRA (Inflation Reduction Act)

See 2022 summary: 23% reduction in total gas+ electric bill; 83% reduction in GHG from burning gas