I was all set to install a continuous flow Rennai 26 gas hot water system, but as it's not exactly environmentally friendly (about half as bad as coal) and talk of gas being phased out (I know that will take 50 years…) but I'd feel better with a cleaner alternative. What are my options here? Solar with the tank on the roof? I'll also be getting solar but not with a battery, yet.
Environmentally friendly Hot water system
Zaxxon on 05/11/2021 - 21:49
Comments
Depending how far north you are, either an evacuated tube solar hot water system or a flat panel solar hot water system.
I have the evacuated tube, and from december to april I don't use anything other than the electricity to run the circulating pump. They are the most efficient way of generating hot water, provided you have the space for them.
These days it's probably more economical to install solar PV panels and heat what water you require with an electric HWS.
Heat pump hot water and solar panels to generate electricity. No need for battery, they don't pay for themselves before their warranty runs out. Join the My Efficient Electric Home (MEEH) Facebook page for expert advice.
Where's the tank? On the roof or stored indoors? Are these common/ easily serviceable?
It goes outside. It looks like a typical storage tank plus a outdoor split system unit. Generally you want the unit where it can get heat.
People would usually put it outside.
They started becoming popular probably around a decade or so ago but seemed to die off in recent years. New builds in gas supplied areas have all gone the way of instant gas HWS. The heat pump storage HWS are more efficient than traditional electric storage HWS, but I always remembered reading about expensive repairs with them. Maybe new ones have solved those reliability issues though.
Personally though I'd put up the largest solar system you can, install an electric storage HWS system and run the HWS off a timer that is set for say 10am-4pm (there are fancier solutions though which can tie in with your inverter and control the HWS based on surplus solar generation).
This… Heat Pump HWS operating on electricity generated from solar panels around noon time would be most ideal. Costs nothing to run and super efficient.
I run my heat pump on off peak power (between 10am and 3pm), and it uses around 1-5kWh (depending on how cold it is, how much use) and I pay about 16c per kWh.
Do you want hot water or not? :)
Take cold showers.