Solar panels, do they reduce the need for oil heating as well as electricity?

Sussex18

Where do the savings actually come from and what are the variables? My house is 50 years old with oil central heating. Do solar panels run smoothly generally?

Thoughts appreciated

Thanks

S

John E.

The savings come from a reduction in your electricity bill due to you taking less electricity from the grid. After that, there are all kinds of variables producing very different calculations of costs/benefits.

As for oil, the only way solar is going to affect that is if you first replace your oil boiler with a heatpump and then use solar electricity to run your heat pump. Otherwise they have nothing to do with each other that I can see.

obriendj

If you use oil to heat your water you can use an eddi which connects to your Solar power. that connects direct to you immersion and uses excess power to heat the tank.

cobham

Space heating and central heating with oil or gas boiler are not replaced by solar. Need for heat is more at night when dark. But you can have a battery and charge up by day to use at night with electric heaters but not practical substitute for winter heat.

steamdave

Using electricity to supplement water heating has meant that my oil consumption has geatly reduced. During the summer (warmer) months when central heating is not required, I use electricity to heat the water so that my boiler is not in use for about 40% of the year.

There are several threads relating to the econmics of the different water heating methods.

Dave

Rows Grower

https://www.boards.ie/discussion/2058351939/solar-panels-do-they-reduce-the-need-for-oil-heating-as-well-as-electricity

If you are also heating water with oil and switch to solar and a dual cylinder you will save big money over time. The dearest part of heating water is getting it from cold to 7 degrees and a sloar panel will do this for free even on a cloudy day.

cnocbui

Ireland's average annual temperature is 10°C, and that would be the average water temperature. It would be fairly rare for it to be below that, let alone below 7°.

WIth a house that old, a heat pump that could be run partially off solar would necessitate major insulation and air tightness work to the house, possibly running to six figures. You are unlikely to break even on the minor cost savings on oil, after doing all that plus the heat pump, in your lifetime.

Reducing heating costs is likely best done with increased insulation, if that is less tha it could be.

drury..

https://www.boards.ie/discussion/comment/122148091#Comment_122148091

I thought the electrical energy required to heat water was constant

slave1

The element on an immersion is resistive so can vary in it's utilisation e.g. a kettle will use 3kW constantly and needs 3kW feeding into it, an immersion can "do" 2.8kW but will also take any feed e.g. 300w and still trickle heat on a bad cloudy day

drury..

I mean the energy required to raise water a degree C

Dont think that changes over temp ?

janmaree

I live in a much older house and have to deal with the cost of bulk lpg for heating, so I increased insulation and installed solar and eddi. I also bought a Dyson heater and a couple of dehumidifiers, the dehumidifiers deal with any dampness as a dry house heats more easily and using one in the utility room makes my dryer redundant. During the winter the solar isn't as active so the Dyson provides daytime heat on the solar and nighttime heat from the grid. The changes have resulted in being able to use the gas heating on a very low setting whenever it's on. The eddi only heats the water when there's surplus generation but it's very effective and still leaves generation time to do laundry and other power related housework. I hope this helps a bit. P.S. I'm so frugal with the gas now that my supplier wrote to me trying to arrange a pickup of my bulk tank since it was so long since my last fill! Understandable I guess but there you are!

DC999

https://www.boards.ie/discussion/2058351939/solar-panels-do-they-reduce-the-need-for-oil-heating-as-well-as-electricity

1. "Do solar panels run smoothly generally?" Yes, and not even 'generally' - all the time. Bar a power cut (when they won't work unless you get a slightly more complex change). I'm live nearly 2 years and never had an issue and you don't see issues mentioned here for the most part. No moving parts in the panels so little to break. The inverter (that the panel connects to) will need replacing at some point, as will every electrical and mechanical device. But they all have warranties for X years and tend to be very reliable.
2. I’ve cut right back on gas usage as others have said here. Not my primary intention but a helpful positive side-effect

Have a look at the quotes thread here to get a sense of the ballpark cost.

graememk

https://www.boards.ie/discussion/comment/122148091#Comment_122148091

Are you talking solar thermal or solar pv

Although It is a misconception that from cold to 7 degrees takes more power.

It takes the same amount of energy to heat from 1 to 7c as it is from 7 to 14 etc.

But solar thermal will be able to transfer more energy the colder the tank water is.

JayBee66

If you are thinking of solar PV then another option is to replace your oil boiler with a gas boiler. You must then be with (or switch to) an electricity company that also supplies gas. You would then use the credit from your PV to pay for the gas side of your bill.

If you are frugal with electricity and can fill a roof with more PV than you'll need then that is doable.

I have thought about that myself but wish to exhaust the possibilities of a heat pump or exhaust myself with worries about the risks. I have radiators but don't trust the results of my heat pump survey.

MicktheMan

https://www.boards.ie/discussion/comment/122153210#Comment_122153210

I have radiators but don't trust the results of my heat pump survey.

If you want to be sure you are heat pump ready then run your current oil heating system as if it were a heat pump; i.e. set the flow temp at 40 degC* max during the coldest spell and see if the house is comfortable.

*This can be easily done by installing a pipe stat on the flow and interlocking it to the burner circuitry such that it kills power to the burner (but not the cuirculating pump) when flow temp goes above 40 DegC.

JayBee66

https://www.boards.ie/discussion/comment/122154459#Comment_122154459

I would, if there was any oil left in the tank. It's been dry for three years.