That's a tough call without monitoring, and the difference will be huge depending on SEER rating, insulation, usage habits, and location. You really have to consider worst case, not averages.
For example, at home I have an older 5-ton, 13 SEER in SW Florida, one of the most challenging areas in the country (high humidity and heat). My annual average is 22kWh per day. We keep the air on 75F generally. However, my average is 40kWh per day in August! When running it draws just under 3kW. A new multi speed scroll compressor unit with high SEER would probably cut my usage by 40% based on anecdotal information I've gathered over the years. It would also drastically reduce startup surge. My home is also older with poor windows and doors, so a newer home would have much different performance. I have a client with a similarly sized house to mine that was built with efficiency in mind and they consume about half of my electricity consumption. It's a tough design question for sure without data. I don't like these situations. In my opinion you really need to overshoot, especially on the battery capacity if it will be hard to add later. Obviously that gets expensive. Jason Szumlanski Florida Solar Design Group On Wed, Jun 23, 2021, 2:16 PM William Miller <will...@millersolar.com> wrote: > Friends: > > > > In the old days when a client suggested they might want to run air > conditioning equipment on an off-grid system we would just laugh. Now I > find I get that request more frequently and clients are willing to pay to > acquire enough system capacity to run AC equipment. > > > > This means I need to size off-grid installations appropriately for the > loads. I have a job pending with a 5 ton AC unit. I cannot find real-life > energy specs. > > > > I do have a new, fairly efficient 3 ton unit at my grid-connected home and > I do have energy monitoring. On a real hot day recently we used a little > less than 11kWh in this unit. The max power draw was about 2.5 kW. > > > > Here are my questions: > > > > 1. Can I linearly extrapolate my usage to a 5 ton unit? > > 2. Do any of you have real-life, measured energy data on modern AC > condenser units that you would be willing to share? > > > > Thanks in advance! > > > > William Miller > > > > Miller Solar > > 17395 Oak Road, Atascadero, CA 93422 > > 805-438-5600 > > www.millersolar.com > > CA Lic. 773985 > > > > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > >
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