Energy efficiency advice needed

(Philip Glasson) #1

We have lived here in Paradise for seven years now in a lovely old house that in recent years has been added to, renovated and generally upgraded into the comfortable home that it is now.
Unfortunately, it’s evolution has meant that the energy system (electricity and tanked gas) has grown a bit like tipsy without much concern for efficiency.

It’s a 4 bedroom house with an attached one bed gite. We have an large, unheated swimming pool and a new hot tub. Our main heating in winter is via a wonderful wood burning stove and our water is heated by three “ballons” and our cooking and central heating is by tanked gas. We are on “Heures Creuse, tarif bleu” with a 12 kVA supply.

Our EDF annual bill is approx 4,000€,
We spend about 1,400€ on tanked gas each year (this is down by about 1,000€ since installing the wood stove)
Our wood stove burns about 2 steers of fuel (600€) per annum.
This gives a total of almost 6,000€ total energy consumption per annum. Our local friends in similar properties pay much less and we would like to do so as well.

Two independent electricians have checked our supply and confirmed that our electricity meters are correct and have helped us make modest changes, but what I think we need more than anything is an impartial energy adviser who can point us in the right direction for perhaps major changes to our entire energy system. It may mean solar/photovoltaic panels or other methods about which we have little current (?) knowledge.

Can anyone please help with contact details for such a paragon?

Many thanks for any help you can give.


(John Withall) #2

Can’t help with a name but insulation first. We put off our renovations, then went for it with multifoil to seal the roof spaces backed up with 200 mm of rock wool. Made a huge difference to both comfort and wood usage, now able to heat the building with the woodburner where I thought we would need a bigger one. Also insulated around the hot water cylinder and despite it having some insulation anyway the water stays warm for about an extra 1.5-2 days.

(Mark Robbins) #3

Blimey, do you like it hot? 4000 euros is an awful lot of money for electricity. I would turn the electric heaters off and rely more on your wood burner, but find a much cheaper wood supplier. One stere (1m3) is normally €50 maximum.

(John Withall) #4

The cost of a stere our way depends if the timber is a metre long or 330 or 500mm etc.

More on the swimming pool as big savings can be made there.

(Chris Elliott) #5

The obvious starting point is insulation - followed by more insulation. It will generally give you quicker returns - roof space obviously - I’m insulating between floors as we go partly for noise partly to keep heat in the living rooms - our cellar is the other issue I have to fix - better doors and insulation.

Double glazing … expensive but generally pays for itself in a sensible time frame.

Turn lights off when you leave a room … but also switch to LED bulbs.

Heures Creuse is the off peak one? Rarely worth it these days - seen the sums and its quite a lot of overnight power usage needed.

3 balloons ? That sounds expensive - logically one large water heater should be more efficient than 3 small

(John Withall) #6

Please explain your logic, as it doesn’t align with mine if full water is not required all year.

(Jane Jones) #7

Perhaps he meant a cord, not a stere? As just 2 for heating all year isn’t very much?

(Jane Jones) #8

Round our way there is a company who specialise in renewable energy, and they will do a diagnostic for you to set out options. Obviously the purpose of to sell you something expensive, but that’s not an obligation. They basically confirmed what we had thought which was useful, and then we allowed them to sell us a wood stove which was what we wanted in the first place! There’s bound to be similar near you.

Agree with others that first step is to look at reducing consumption (light bulbs, switches, etc), then insulation including things like thermal lined curtains, then upgrading windows and doors. Also look hard at whether you a on the right tarif. When we did the calculation we found that heures plein/creuse was costing us money not saving it…

We have 4 bed old house, plus 3 bed gîte, in a cold area of France and orientated so don’t get sun early (beside a cliff). Our energy costs are significantly lower than yours.

(stella wood) #9

Chris… I agree with everything you said… until you got to the water heater bit…

I shall follow that aspect/discussion with interest as we are considering putting in an electric water heater/ballon to use in the summer, instead of the “instant” oil-boiler (with internal ballon).

Mostly we are just 2… but on occasions we have a houseful and need to find best solution for all … so one large… or 2 smaller to use as needed … ???

(Michael Archer) #10

We also have 3 ballon in our long farm house as recommended by our French experts in plumbing and heating and there are only 2 of us but lots of family visitors, the main reason is the distance that the hot water as to travel before it reaches it’s required destination and the quantity used.

(stella wood) #11

Yes, that is an important consideration… friends in Jarnac have done much the same… they switch-off the one at the far end, when no-one is staying…:relaxed: but their house is much bigger/longer than ours…

(Chris Elliott) #12

Sorry - in general modern water heaters/tanks are well insulated and hold their temperatures for days - for most houses I’d personally have one larger water heater. If you turn them off and bring on them on stream when you’ve guests I see the advantage of several water heaters. But modern systems are surprisingly efficient and hold their temps well - its the initial heat that tends to cost. One large tank will on the whole lose less heat than 3 smaller ones - the heating itself is usually more efficient. I could be wrong mind - its 10 years since I looked at the numbers.

If there’s a Gite - or guest “wing” when no hot water is required a lot of the time then a separate heater would make sense.

I may be wrong - but generally when there’s numerous water tanks one does most of the work - the others just sit there costing money so someone can wash their hands twice a day. The initial post hinted the installation was done a bit here a bit there I made an assumption …

(Paul Flinders) #13

Ultimately if you use x litres of water you have to heat x litres of water and that will cost the same whatever size of ballon you have.

Where different sizes of ballon are going to alter things are heat losses and unnecessary heating of water. All things being equal a 300l ballon heated to 60oC will cool more slowly than a 150l ballon as it has a smaller surface area:volume ratio and heat is mainly lost at the surface - but you have to heat 300l in the first place which costs twice as much and the on-going heat losses for a 300l ballon are 1.6x those for a 150l ballon so you will waste energy if you have an oversized ballon.

Note that 2x 150l ballons will waste even more energy if they are kept hot so the only way to save money with multiple smaller ballons is if they are kept switched off when you do not need the capacity (in turn this will mean that you need to be able to isolate the hot water output so an inactive ballon does not supply cold water into the hot pipes when you turn a tap on).

Finally I think that @mick makes a good point - if having a single large ballon means long pipe runs and those pipes are not well lagged you will waste heat as the water in the pipes cools (and water as you have to run the tap until fresh hot water comes through) so having smaller ballons closer to where the water is used might be better.

The ultimate solution is point of use instant heating which is probably the best option if you have a highly variable usage pattern as you will only ever heat the hot water that you use - I don’t know how common these are in France - a quick Google shows that they are available but I do not know if they are widely installed.

Tl;dr - multiple small ballons might, or mght not be better than one large. :slight_smile:

(Michael Archer) #14

We use two ensuite bedrooms all year round and there is a distance of 23 metres between the two so that was the reason given for having two upstairs and the other one is for the Kitchen/utility rooms.
Just following the advice of the experts.

(John Withall) #15

Problem with instant water heaters in France is you may need a larger supply and or abandonment or the deselectors etc not a problem normally in the UK as we have enough on tap without tripping anything.

OP should look at solar heating of water even if it’s only pre heating at some times of the year and I can testify to increasing the insulation around the hot water cylinder.

Need more information on the pool as these can frequently be the most expensive to run domestic appliance, more than hot water hence the biggest saving. Is there anyone in France you can ask about reducing the energy consumption of the pool except me?

(Paul Flinders) #16


I was going to suggest solar but someone beat me to it (or at least “renewables” were mentioned before I had chance to post). Or a heat pump but that might not be cheaper than gas.

(John Withall) #17

If the OP is considering heating the pool (doubt it with their current outgoings) they could use a heat pump for both the pool and pre heating the hot water.

Evacuated solar reaches the temps required for hot water, certainly something I am now considering.

Just hope OP returns as it was a few days ago they posted and they may not want a discussion.

(Philip Glasson) #18

Thanks for all your responses.

Without going into the detail of the cost of a stere of firewood, (which was not what I wrote about). We can turn off one of the balons (hot water tanks) as it serves only the gite, but the other two are at different ends of the house. One serves the kitchen and the other our main bathroom and there is a fair distance between the two. The pool is not heated and we intend to keep it this way. There are only two of us here for most of the time so the costs are rather ridiculous.

We are well insulated and double glazed, the house having been completely renovated during the last 15 years. The key concern is about the cost of our energy, particularly electricity. We would be interested in renewable energy (Thank you Jane Jones), but, although we are keen to save the planet, we are also keen to reduce our energy bills and it’s professional, impartial advice that would be particularly useful from someone who could assess our entire energy system, preferably someone who could speak English (although this is not essential). It could be a state enterprise or freelance consultant (or anyone in between).

I should perhaps also have said that we live here in the Aude dept between Limoux and Castelnaudary so energy experts in this part of the country would be very useful.


(John Withall) #19

Ah of course, now why would you be using so much energy if the above were true?
The really good news is I am a professional swimming pool engineer and I know large pools consume a lot of electricity and most owners do not recognise this as energy surveys on properties do not include the pool even though it can be the largest consumer of electricity. I give impartial advice, I speak English fluently most of the time. Even if you are successful in locating a technical engineer for your home, I will guarantee they won’t have answers on how to run your pool at maximum efficiency as this field I have specialised in for the last 5 years. It is possible to reduce pool running costs by 90%.

(Paul Flinders) #20

So, err, you have saved 1000€ on gas but spend 1200€ on wood instead - time to go back to the gas?

Even if the pool is currently unheated?