Am fully aware that one of the best ways to heat up a home in winter is to have a heat pump, however if one has installs a solar system with batteries, what would be the most effective way to heat up a home in winter at the most cost effective way? Ideally the method would involve or ensure that the battery systems are not too taxed or strained. Your thoughts forumites would be most appreciated, thanks.

15 hours ago, Moffat said:

... if one has installs a solar system with batteries, what would be the most effective way to heat up a home in winter at the most cost effective way? Ideally the method would involve or ensure that the battery systems are not too taxed or strained.

This could turn into a very interesting discussion... My thoughts:

One would obviously have to consider daytime (good solar harvest) and nighttime (and bad solar harvest daytime when e.g. it is very cloudy or raining) separately.

• Daytime with good yield: Simply use electricity generated by your PV. This assumes that your system was properly planned and "over sized" for this eventuality. I switched on my 2kW electric blower heater at 08:30 this morning, and just charged the batteries a little slower. Currently (11:00) my solar harvest is just over 5.3kW, and I'm comfortably running both my 2kW geyser and the heater from solar, and a 8000 BTU inverter type air conditioner set to heat whilst still charging the batteries at a low 640W. Around 12:00 the heater will be switched off so that my wife can use the stove (the batteries will be fully charged by then). I planned for this when I designed my system larger than normal (12kW inverter), and even though the ROI might not be as good as some people would like it to be, I am enjoying the "luxury" of being practically off-grid and warm during the cold Free State winter 😁

• Daytime with bad solar yield: We use the gas heaters.

• Nighttime: Now this is where we can have a serious discussion about draining the batteries vs running the risk of not having power if there happens to be an electrical outage or load shedding the next morning... and where the esoterics can be thrown around 😉 (How about a "sand battery" heater?). We have under-carpet heaters in the house that are run off the battery for an hour or so at night if really needed, although I don't like to drain my batteries lower than 50% SoC.

Looking forward to inputs from other Forumites...

5 hours ago, HennieL said:

This could turn into a very interesting discussion... My thoughts:

One would obviously have to consider daytime (good solar harvest) and nighttime (and bad solar harvest daytime when e.g. it is very cloudy or raining) separately.

• Daytime with good yield: Simply use electricity generated by your PV. This assumes that your system was properly planned and "over sized" for this eventuality. I switched on my 2kW electric blower heater at 08:30 this morning, and just charged the batteries a little slower. Currently (11:00) my solar harvest is just over 5.3kW, and I'm comfortably running both my 2kW geyser and the heater from solar, and a 8000 BTU inverter type air conditioner set to heat whilst still charging the batteries at a low 640W. Around 12:00 the heater will be switched off so that my wife can use the stove (the batteries will be fully charged by then). I planned for this when I designed my system larger than normal (12kW inverter), and even though the ROI might not be as good as some people would like it to be, I am enjoying the "luxury" of being practically off-grid and warm during the cold Free State winter 😁

• Daytime with bad solar yield: We use the gas heaters.

• Nighttime: Now this is where we can have a serious discussion about draining the batteries vs running the risk of not having power if there happens to be an electrical outage or load shedding the next morning... and where the esoterics can be thrown around 😉 (How about a "sand battery" heater?). We have under-carpet heaters in the house that are run off the battery for an hour or so at night if really needed, although I don't like to drain my batteries lower than 50% SoC.

Looking forward to inputs from other Forumites...

@HennieL funny you mention fault, we actually had a nationwide grid failure in Zim last night from 18:21hrs to 23:17hrs, though power restoration began happening in some areas after the 2hr mark. Am just thinking of relatively cheap 800w to 1,500w space heaters and their impact moreso for me with only 2 x 5kw batteries. Daytime generation definitely is an important consideration and having enough panels important but night time is greater part of any home heating, well save for areas like Capetown where you may get snow and others near Lesotho which can almost be 0º degrees during the daytime at extreme times...

That 800w to 1,500w also pulls a lot over 3-5hrs of evening time, especially where a home or room does not have adequate insulation as well hey.

Edited yesterday at 02:251 day by Moffat
Additional information

1 minute ago, Moffat said:

... night time is greater part of any home heating, well save for areas like Capetown where you may get snow and others near Lesotho which can almost be 0º degrees during the daytime at extreme times...

We really suffered in the Free State when we experienced the sh**ty unseasonable Cape Town winter weather the last two months - I'm really glad this is the exception, and not the rule... Even though we dropped down to -2 - -3 degrees the last few days, clear winter skies still allowed for very good yield this past week.

Regarding night-time heating, the only practical solution would be to store heat (electricity) during the day for use at night. I also like the idea of building a "sand battery" heater, but unless one is prepared to make a large container with sand a feature of your living room or study (or bedroom...), there is no practical way to a) store the container out of the way while it is "charging" during the day and b) moving the container around to where it is needed whilst hot (and heavy...). One practical method would be to use an oil-based radiator heater (like they use(d) in schools and hospitals), have the large sand battery located outdoors, and run a heat-exchanger type system between the radiator heaters and the sand battery - quite possible, and relatively easy to construct, but expensive.

For surviving on minimal power, a 400W wall panel heater per room, then close interleading doors and only heat the rooms you need. Or electric blankets.