Pilotabroad

Thanks for clarifying, glad I'm not going mad 🤣

Pilotabroad

Interesting read earlier regards why underfloor heating is 95% of the time installed downstairs only.

Its regarding the importance of insulation.
Using an EPS with concrete slab underfloor can be operated at 35deg rather than the 65deg radiators require, obvious energy and cost saving.
However as 95% of Western buildings still use timber beam floors in uperfloors, even with top spec insulation it increases the temp demand to nearly the same 65deg cancelling the saving.

As an aside the use of concrete slab or block/beam floors upstairs in the west are generally in countries with a much warmer milder climate so often underfloor is still only fitted in the lower floor regardless.

As I'm fitting concrete slab downstairs and concrete block upstairs I'm fitting it to both floors, hence the previous mentioned internal airsource heat pump is interesting (noise, efficiency, etc of concern)

1Steve

@BillBullock Where did you source your night storage heaters? I have been searching here in Portugal but not having much success. There are plenty brick or oil filled radiators but they are not storage heaters that you can charge up and use later. If anybody else knows of a place to source storage heaters please let me know, thanks

Alan PT

I thought that bricks were exactly what was in a night storage heater? The electric element heats them up during the night, they have a high thermal mass and slowly release that heat during the day.

I'd question whether they are worthwhile in Portugal though, the night rate is for a shorter period and at less of a discount than in the UK. Better to invest in an air/air or air/water heat pump, which are very efficient here, due to the lack of extreme low temperatures

1Steve

Thanks for the info Alan. I believe a true storage heater has dampers/flaps that restrict air flow over the bricks to store the heat so that you can open them when you want to get the heat out of the bricks. I have looked at several heaters here but they do not have that, they immediately/slowly release the heat by convection/radiation. Maybe storage heaters are not so efficient and the modern heaters are more economical. I am still researching but my original plan was to install solar and load the storage heaters during sunlight and use the stored heat at night. Any further advise very welcome as I have one very cold house to heat up. Roll on summer

Alan PT

My experience of storage heaters was 15-20 years ago, so they might have improved. Yes, I do remember they had some controls to release the heat more or less, but in my experience they had limited effect. It was still giving out a reasonable amount of heat even with everything closed. It's an interesting idea though and I can see the logic of using "free" energy during the day, but efficiencies will be low and the capital cost is quite high when you include the panels.

If you can spend some money "up front" then maybe the most cost efficient way to spend it would be on insulation. Having lived in some "normal" Portuguese places for the first two years and been cold in spite of soaring bills, we moved to a new place that's A rated - it's not some super zero energy home, just has a moderate amount of insulation (as you'd find in any UK house from the last 30 years).

I know it may be difficult/impossible to do, depending on the nature of your property, but if you can find a way than it's definitely worth investigating. The difference is incredible, it's probably 6 degrees warmer than outside before you even turn on any heating. We also installed some efficient aircon units which also do heating, but even before we had those installed we were finding that a little 2kw fan heater would very quickly heat up the room.

BillBullock

Just catching up after a day or so off. Firstly, the off-peak period in Portugal (called bihorario) is from 2200 hrs to 0800 hrs (10 hours). I seem to remember it was only 8 hours in the UK. I installed my night storage heaters about 10 years' ago and shipped them in from the UK. They have become more advanced since then but mine have automatic controls on input and output. In our late 70s, we enjoy a warm house when we get up and, in the evening, the heaters are still giving out heat, especially in our bathroom where it is still 22-23 degrees C on a cold winter's evening and I strip off for a shower before bed. Any fool can have a cold house in the winter but ours never drops below 21 degrees C, even on the coldest winter day. Our 26 year old house has cavity wall insulation but not to a very high standard so I doubled up on the loft insulation (yes we have loft space almost everywhere and it was easy to lay styrofoam sheets throughout after we first moved in 19 years' ago).

In our first year I stripped out the central heating radiators because the boiler ran on bottled gas and the price was going through the roof (we live in the countryside where there is no gas supply). The price of electricity doesn't seem to have gone up at the same rate which is the reason I went for electricity to heat the house. Night storage heaters in my opinion are a good solution if you choose electricity for heating because of the 10 hour cheaper rate period but, most importantly, because the house does not start cooling down rapidly when the electricity supply switches off, unlike when other electrical heaters are turned off. I am still happy with my choice of heating as it suits our way of life, given the limitations of living no campo.

Alan PT

UK has/had a few variations of E7 & E10 so yes, you are right, Portugal is not shorter, my memory failed me

You can also get a madly complicated version in Portugal which varies by day of the week and whether it is Summer or Winter, not really sure why!
https://www.edp.pt/particulares/apoi...-mim/faq-4823/

coleio

Storage heaters have changed and are being used (maybe not in Portugal yet) with domestic solar/wind as storage in place of battery storage, also combined with "smart" grid connections quote " Half-hourly electricity prices that update daily based on wholesale costs. Shift your energy use outside the 4-7pm peak to save money. " so set a rate and anything below that rate causes power on and directed to the storage heater. The storage is basically high thermal density, high temperature very well insulated "fridge" sized box, hot water on demand and radiator heatings extract heat from the storage. Stuff like (I have no connection with)Half-hourly electricity prices that update daily based on wholesale costs.

Shift your energy use outside the 4-7pm peak to save money.