I have had my Rheem PROPH80 T2 RH375-SO 80g UEF=4.0 since early October. It is installed in my garage and is set to heat to 138F with a mixer that takes it back down to about 128F. I also have a recirculation system with an Alexa controlled plug for the pump that we can give a voice command to run for 2 minutes prior to getting in the shower. With the following real world results:Where do you live and how long have you had the Rheem hybrid? Like any heat pump, its COP and how much heat it can deliver dramatically depends on the difference in temperature (another reason I'm not a fan of ratings that show a single BTU/hr or COP value or whatever the units are any more than single mpg or Wh/mi values that assume you're always driving in specific conditions at a specific speed). The 4200 BTU/hr rating was likely measured under the standard test conditions:
Monthly Total kWh
Monthly Average kWh/day
Cumulative Average kWh/day
Worse case was in December with the colder ambient temperature and six people in the house instead of 2. I set the controls from Energy Saver to High Demand when we had 6 people in the house, but the logs don't appear to show any electric element usage during that time. Nor have I seen this at any other point even after filling a bathtub with 65 gallons of water.
I went from using 29-32 therms/month during the summer to just 2-3 therms/month for a savings of about 28 therms/month with a hotter water temp (I had turned it down trying to reduce costs). During the summer, the baseline is only 0.49/therm per day or 14.7 therm/month. So 11.7 therm at the Tier 1 cost ($1.97953) and 16.3 therm at the Tier 2 cost ($2.44752) which is $63.05. During the winter with gas heat all of the savings would be at the Tier 2 costs ($2.50 avg for Nov'21-Mar'22) so that would be roughly $75.00/month. I expect to save $815/year in gas costs with a reduction in my net exports of 850 kWh which at $0.088 (SVCE NSC is twice PGE NSC) is worth $74.80 for net savings of $740/year. After a $2,000 rebate from SVCE for switching from gas to electric hybrid I will pay off the installation cost in under 5 years.