Energy efficient heating advice

chelle_icky

Hi - we recently moved into a barn conversion property and are now considering our options for upgrading the heating solution and would really appreciate some advice from the experts on here.

Relevant details are:
- conversion completed in 1980s
- solid stone walls, no additional insulation
- open plan downstairs (6.5m x 5.5m), with open staircase
- 2 bedrooms upstairs, small part attic but mostly high ceilings up to the roof apex, so limited insulation there too
- we are 1 of 4 houses in the old barn, so have only 2 outside walls
- there is no gas in our village

Currently the property has storage heaters, now over 20 years old (Sunhouse), one in each bedroom & only one in the single room downstairs. We also have an ancient multi-fuel stove with back boiler feeding a single towel heater in the bathroom & a hot water cylinder (which we never heat up through electric, although it is an option). We do use the stove as our top-up heating, but it never gets us to the point where the room feels too hot - it seems to divert most of the heat to the boiler. We are planning to replace this with a more modern & more efficient stove & back boiler, keeping our ‘free’ hot water option.

The house is never particularly cold, but never feels cosy either. It doesn’t feel draughty, but we do, understandly, have cold spots, particularly in the corner opposite to where to the storage heater is located downstairs.

We are currrently trying to obtain planning permission for 8 solar panels to be fitted to our roof & are intending to fit battery storage as well - we’ve been quoted for an Ecoflow battery & inverter system with 2 x 5kwh batteries, & the option to add another 5kwh battery in the future should we want to. We are thinking we can top up battery storage with our Eco7 rate electric, as necessary.

The current dilemma is whether we upgrade the storage heaters, which will possibly mean adding a second heater to the downstairs space, or install ThermaSkirt-e. I could see that the heated skirting would provide a more holistic heat & therefore create a more cosy feeling, but I’m nervous that it will cost us a lot more to run, and really not sure if the battery stored power would be sufficient to run such a system. I’m wary of getting in a heating engineer to provide a recommendation because I want the best solution, not just the most profitable for a fitter / supplier! Any recommendations for a truly independent expert, who has good knowledge of these options would be very welcome :)

Oh, and we are a retired couple, so home on & off throughout the day.

Screwdriva

When it comes to poorly insulated properties, my first question is always: what is the budget you have to spend? I'll add - whereabouts in the country are you located?

chelle_icky

We’re located in North Yorkshire, just inside the Dales National Park (hence the planning requirement for panels). It’s pretty exposed here, but using today as an example: it’s 4 degrees out, feels like -4, according to my phone, and whilst you’d never describe it as cosy in here, it’s certainly not cold….yet. And I don’t have the storage heaters turned up full.

In terms of insulation budget - we don’t have much to spare, plus we don’t really want to change the character of the property.

QrizB

The current dilemma is whether we upgrade the storage heaters, which will possibly mean adding a second heater to the downstairs space, or install ThermaSkirt-e.

Given the choice between storage heaters or direct electric heating, I'd choose storage heaters. Direct electric heating will cost roughly double to run.

See link in my signature for some comparative costs for a typical home (accepting that yours might not be typical).

Is there any possibility of installing a heat pump?

Heedtheadvice

You might not want to change the character but the best result from financial outlay must be as much insulation as possible. However you heat, much of it will be heating up stonework which will retain some but be constantly losing it to the exterior. Similarly losing it ( but much faster though) the roof.

IMHO only after that is considered should other green measures be in the equation.

If finances remain after allocation funds for insulation and you will have pennies left over then there could be lots of options with an efficient fire (especially if you have access to cheap dry fuel) and taking advantage of the cheap electricity price overnight in 'winter' periods and solar generation in 'summer'.

Reed_Richards

You will use pretty much the same amount of electricity to run the ThermaSkirt-e heaters as you use to run your storage heaters (more electricity if you want to make it warmer). But the amount you pay for that electricity will be different. With storage heaters all or most of the electricity used for heating will be charge at your night rate. With the ThermaSkirt-e heaters most of the electricity used for heating will be charged at your day rate (or you might move to a single rate, which will be a bit cheaper than the day rate on Economy 7 (or similar).

chelle_icky

@Reed_Richards - this makes perfect sense to me. So I guess the big question is…..can I run the ThermaSkirt-e heating from a battery? This will have been charged up by solar (hopefully) else Eco7 night tariff, so if there’s sufficient capacity I get it on the cheap.

I’m sure there must be a way to come up with a reasonable / educated guess on how much electric we’d use in the ThermaSkirt-e heating, but I don’t know how to do that. If I had that I could then look at battery capacity vs consumption, thus understanding how much free / cheap / costly energy I’d be using.

NedS

https://forums.moneysavingexpert.com/discussion/comment/81958595#Comment_81958595

If @Reed_Richards statement is correct, that you will use the same amount of electricity to run the ThermaSkirt-e heaters as you use to run your storage heaters, then you already know how much electricity you will use, from your current usage. The difference will be that it will now be spread (more) evenly over a 24h period rather than condensed into the Eco7 night time period.

This should allow you to appropriately size any battery.

Something else to consider if you have electric heating and a battery is switching to a tariff like Octopus Cosy, where you get 3 cheap rate slots spread throughout the day, giving you 3 times per day when you can recharge your battery. This allows a smaller battery to be installed as the maximum time between cheap slots is only 6h so you only need sufficient battery capacity to last 6h in winter. Having to recharge a battery overnight on Eco7 and then last through to the following night will require a significantly larger battery in winter.

LessImpecunious

The fact that your house doesn't ever feel cold suggests that you might not need to worry as much as some have suggested about adding extra insulation - uninsulated stone walls can act as a thermal mass, and (this works well in a house where you have a relatively low continuous heat (e.g., heat pump, or, (I assume) storage heaters) - sounds like your walls may be doing that already.

QrizB

I'll just mention that fancy storage heaters are roughly 1/3 the cost of cheap batteries, on a per-kWh-stored basis.

A Dimplex Quantum 150 (my benchmark fancy storage heater) stores 23kWh and costs £1150, £50 per kWh.

A cheap Fogstar battery and inverter (48kWh, equivalent to two of those Dimplex heaters) is £7300, about £150 per kWh.

If you wanted a fancy battery like a Tesla Powerwall, you're looking at £500 per kWh.

Storage heaters are still the cheapest option for stored heat. (I wish they weren't, but I can't argue with the numbers.)

This will have been charged up by solar (hopefully) else Eco7 night tariff

In the current market, you might find you're able to sell your homegrown solar electricity for more than the price of replacing it at night on E7 or similar.

I don't know how long that will last but using solar PV to provide heat isn't always the best financial option.

Heedtheadvice

The comment about stone walls being a thermal store is quite true. You heat them from the power you buy and they will give back some of that heat when the interior of the property is cooler than the stone. Rather on the same principles a storage heater works.

Like underfloor heating it is a gentler release of low temperature stored heat -so more like a background heat. They also take longer to heat up from cold to be as warm as the air convected across their surface - as well as some radiant heat gained from a hot source like a fire.

The downside ( as well as that 'heating inertia' ) is that the heat is also released from the external side of the wall...and whilst the outside is cold/colder than the inside that heat which is lost is considerably more. One pays to provide that lost heat.

Why on earth do you think thermal emissions form part of assessing heating needs?

OK when the outside is warmer than the inside the reverse is true, partially, but as gains and losses are temperature difference dependant, winter heating cost is higher than any summer cooling need. When it is below zero outside and the interior is 20 C degrees ( 20+ differential temperature ) the heat lost far exceeds the few days of 30degrees outside - just 10 degrees differential temperature. Add to that heat to dry any wet stonework and wind cooling...

( assumption property is maintained at 20)

Insulation really needs to be addressed. Not that you are likely to reach Passivehouse standards or wish to add insulation to the good current Building Regs standards?

Some excellent posts regarding good ways to get the heating required but that should not be treated in isolation.