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Xringer · 06-28-12, 07:56 AM

The big difference is the power (KWh) used to heat the water.
The resistive heating element uses a lot of power. (1 KWh for each 3412.142 BTU).

Whereas the HP is just moving heat, out of the air, into your water tank. (Using less power per BTU).

Yes, the HP is slow. So, if you are in a big hurry to take a shower, right after doing a wash, the standard hotwater heater is for you.

But, if you know how to plan when you are going to shower, the HP will save you some money on power.

Today, we will spent about $2 for oil, to heat our water.
I think this A7 ASHP will cut that down to about $1. (If it uses 6 kw hours per day).

I think the HW ASHP is not very popular because of it's initial cost.
And because people know that regular HW heaters will fail, many times, within 5 or 6 years.

~~~
Today, I'm considering the size of my tank.. The A7 is good for up to 70 gal.
But, if demand is low..(Ours is quite low) Maybe a smaller tank would be cheaper to run.?.
Instead of a 50 gal, maybe a 40 gal tank would be more efficient?
Less water, less leakage (smaller surface area of tank)=less KW hours?

06-28-12, 07:56 AM	#42
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	The big difference is the power (KWh) used to heat the water. The resistive heating element uses a lot of power. (1 KWh for each 3412.142 BTU). Whereas the HP is just moving heat, out of the air, into your water tank. (Using less power per BTU). Yes, the HP is slow. So, if you are in a big hurry to take a shower, right after doing a wash, the standard hotwater heater is for you. But, if you know how to plan when you are going to shower, the HP will save you some money on power. Today, we will spent about $2 for oil, to heat our water. I think this A7 ASHP will cut that down to about $1. (If it uses 6 kw hours per day). I think the HW ASHP is not very popular because of it's initial cost. And because people know that regular HW heaters will fail, many times, within 5 or 6 years. ~~~ Today, I'm considering the size of my tank.. The A7 is good for up to 70 gal. But, if demand is low..(Ours is quite low) Maybe a smaller tank would be cheaper to run.?. Instead of a 50 gal, maybe a 40 gal tank would be more efficient? Less water, less leakage (smaller surface area of tank)=less KW hours? __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less.. Last edited by Xringer; 06-28-12 at 11:45 AM..