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
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.
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.
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.
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
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.
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.
I thought the electrical energy required to heat water was constant
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
I mean the energy required to raise water a degree C
Dont think that changes over temp ?
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!
Have a look at the quotes thread here to get a sense of the ballpark cost.
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.
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.
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.
I would, if there was any oil left in the tank. It's been dry for three years.
What is the procedure for applying for a grant? By that I mean do I have to get and pay for a Ber assessment myself? Do I have to contact multiple companies?
Kind regards
Generally the order is
Get quotes, once happy with a quote, you apply for the grant (you have to choose a supplier at this point)
The quote may include the ber, or they may require you to get one(although most quote with a ber now)
Contact multiple installers for quotes, try to get a good idea of your requirements and what you hope to achieve beforehand so you don't get taken for a ride
Installers will either give you a quote inclusive of the grant or not. As I recall they start the grant process and you receive an email from SEAI to fill in your details and confirm the grant application
Post installation the installer will complete the paperwork and assuming there's no issues the grant will be paid. Either it'll pay directly to the installer and they'll deduct the amount from the final bill, or you pay the installer the full amount and then the grant is paid to you. You'll want to work this out when getting quotes
In terms of money savings, the solar panels will reduce your electricity usage by trying to supply power to the house from the panels. If the demand from the house is greater than what the panels can supply at that time, then you'll import power from the grid
If there's more solar power available than demand, then the excess will be fed back or exported to the grid. If you have a smart meter then you'll be paid for this export, the rate depends on your electricity supplier
A lot of folks use a battery as an energy storage device, meaning you can store extra solar power and use it later. Alternatively you can charge the battery on cheaper night rates and use it during the day, while exporting as much solar power as possible. This works well at the moment because the rate for selling power to the grid is quite good and higher than the night rate
In terms of reducing oil, you can use a device called a diverter to run your immersion heaters when there's excess solar power. The most popular one is called an Eddi, but there are other brands
This will give you free hot water on sunny days, so in turn you won't need to use oil
As for heating your house, this can be done but adds complexity. Plus you need to deal with the fact that during winter the heating demands are greater and there's less sunshine
My advice would be to keep it simple from the standpoint of solar panels for now and just install a system which supplies you electricity and sells excess to the grid, plus maybe the diverter and a small battery if you think you'll need one.
I'd generally recommend installing as many panels as you can up to the limits to maximise your returns from exporting electricity
For heating, improving insulation and air tightness is likely a better first step than looking at different heat sources
A good sound summery there Raisin! I would make the point of installing the max amount of panels to start with as it is not easy or recommended to add them bit by bit. Individual panels are not the main expense of an installation.
Yeah fair point, no need to go too overboard particularly if on a budget. It's probably worth having some spare inverter capacity if planning to expand later
I've noticed a lot of the cookie cutter systems tend to be quite small and often not the best value. I'd generally feel it's better to oversize the system slightly and either use the extra generation or earn more from export
It also leaves room to expand since people often find creative uses for free electricity
I forgot they were asking about the BER as well 😅
My experience was that the installer included the updated BER assessment in the quote, but post installation they were having a lot of trouble finding an assessor
They said I could wait or find my own to get the grant faster and they'd refund the €300 charge for the assessment
In the end we went with our own which cost less than the €300 so it worked out well
To the installers credit they were very upfront and honest with the options and the refund was transferred in a day or so of the assessment being done. They also had the grant paperwork in the day of the installation
Having a good installer who gets the paperwork side done as well as the installation works really helps IMO
Or you can just DIY it, but I've so far failed to persuade my wife that I won't electrocute myself or burn the house diwn, so not an option for me
For me, I got an Eddie with my solar inatall, which means I dint use the oil to heat the water anymore.frkm.march through to Oct.
Solar panels can indeed help reduce your need for oil heating, especially if you pair them with a solar-powered water heater or a heat pump. The savings primarily come from generating your own electricity, which reduces your reliance on the grid and cuts down your utility bills. The variables to consider include the amount of sunlight your location receives, the efficiency of the solar panels, and the current state of your home’s insulation and energy use. Given that your house is 50 years old, you might want to also look into improving insulation to maximize the benefits of solar power.
How does the E2100 Grant work? Is there a minimum number of panels required to get this? Or is it a specific amount per panel?
All information is here
Solar Electricity PV Grants | Home Energy Grants | SEAI
Grant name
Value
Example
Solar PV grant
€800 per kWp up to 2kWp
€1600 for 2kWp solar panels
€250 for every additional kWp up to 4kWp
Total Solar PV grant capped at €2100
€1850 for 3kWp solar panels
€2100 for 4kWp solar panels
