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New central heating solution


HQ
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Hi everyone

A newbie to the site, so be gentle although I have read many-a-posts and have found them informative and very interesting.

We are currently in the process of waiting for the Notaire to finish off the paperwork and hope to collect the keys next month. It will be our holiday home (for now) and is located in Bourganeuf, 23400. However, there is quite a substantial amount of work needed not all of which are decorative - we are quite capable with the latter. Items on the big wish-list include:

  • Remove a separating wall between kitchen & dining room
  • Move an internal wall
  • Close off several internal doors and create 2 new ones
  • New central heating
  • New bathroom/shower room and a cloakroom
  • New kitchen

One of the key changes we will need to put in is a heating system. At the moment there is none (or rather some old electric heaters and balloon-type for hot water). We are looking at options although the variety of choices from this forum seems to make it rather mind-boggling - being not a plumber and all.

The simplest option seems to be just keeping the existing electric system and replaced the heaters. This would be very straight forward although doesn't give much flexibility as there still need to be a solution for DHW, etc.

Another option we are exploring, given the existence of a fire place in every room, is to install a wood-burning stove combi boiler either in the kitchen/diner (where we expect to spend most of our time) or the living room and to have wet radiator system. This would be identical to what we have in the UK, except for the stove. However this will require quite extensive plumbing for the entire house but it would also solve the DHW issue. If necessary we could also have a simple log-fire in each room although more likely for aesthetic than functional.

Some searching on this site and the web seems to throw up quite a few other alternatives although I am unfamiliar with most of them. Does having a "generic wet system" as above a good solution or are there more suitable alternatives?

Would appreciate any advice, Hung

 

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Err, maybe I am not asking the question correctly Confused [8-)]

Has anyone put in new heating system recently and what considerations did they ahve to go through? Not being a lmber am I on the right track in my thinking or am I limited ot what is the norm in the UK (perhaps there are French systems that are not common in the UK)?? Any advice from experts out there?

 

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[quote user="HQ"]

Err, maybe I am not asking the question correctly

Has anyone put in new heating system recently and what considerations did they ahve to go through? Not being a lmber am I on the right track in my thinking or am I limited ot what is the norm in the UK (perhaps there are French systems that are not common in the UK)?? Any advice from experts out there?

[/quote]

HQ, let me use your above comment as a starter.

Your house is in France, norms in the UK are irrelevent, French Normes, rules, regulations and codes of practice are VERY relevent. There will be areas of UK/France conformity but.....there are lots of things you can do in UK but not in France. Meet the French rules and you will be safe and legal. If you do (many) things the "UK way" you will be in for grief / expense etc etc.

No one here can tell you what heating system or method is best for you, its dictated by your own personal likes / dislikes, requirements, family circumstances, financial circumstances etc. There are, as you have found, many posts regarding individual ideas about which way to go, we all have our own opinions but ultimately its down to you and your own opinion.

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HQ,

As powerdesal says, you'll need to stick to French standards, but here are a few comments from first principles.

Open fires are a great way to keep the local birds warm. The efficiency of an ordinary fireplace is tiny and even when you don't have a fire lit warm air is still pouring up the chimney. If you do want fires then go for stoves or 'inserts' -- these are like fireplaces with a glass door and make a huge difference to how warm you'll be.

As a generalisation, going for a wet heating system is the most flexible option because you can heat the water using any fuel. That means you could put in an oil burner (I wouldn't, but just as an example) now and change it to a ground source heat pump (GSHP) later. You'll need to plan the system right, though.

People have preferences about underfloor v radiators. I'd go for underfloor, but you may differ.

The best thing you can do is concentrate on insulating and draught-proofing your place to the highest standards you can because that makes heating easier and life more comfortable. You can end up needing a much smaller heating system -- new builds can get by with hardly any.

Another thing to consider is proper ventilation. A whole-house ventilation system with a heat exchanger ensures that most of the heat in the stale air is transferred to the fresh air coming in. In winter it makes more sense than opening windows. They are reasonably cheap, all things considered. Look for 'mechanical ventilation with heat recovery' -- in French look for "VMC a double flux".  

http://www.promotelec.com/technique/dossiers/24/dossier_2.aspx

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Hi HQ and welcome to the forum

A lot of sense in what has been said above.  Ultimately it's down to your budget but as I'm sure you know, it's essential to have the system you use installed by a reputable firm, preferably on recommendation for someone.  Since it is a holiday home, imagine wondering about the security of the system (water/gas/electric/whatever) when you're not there.  Have it installed 'on the black' and if something were to go wrong the you can bet the insurance would wriggle out somewhere.

Just some thoughts based on my own circumstances.  Since it is a holiday home (maybe you intend to move there permanantly later) you might want to think about capital costs vs usage.  Yes sure, geothermal plus solar plus underfloor has great merits but at a price. Do you really want to go to the trouble and expense of a full wet system for something you might use for only a few weeks of the year?  I have 2 wood burning stoves and gas (big tank in the garden) wet central heating which was already installed when I bought my house. A big thing for me is the ability to heat the house quickly especially if arriving late on a cold winter's night.  I generally flip the gas heating on and light one or both of the stoves.  By the time I've unpacked the car, the chill is taken off and it's OK inside. At this point I throttle the gas heating right back (coz I'm mean) and let the stoves do their thing and the lounge and kitchen get warm quite quickly.  Admitedly it can take 2 or 3 days for the whole house to become toasty warm all over but I wouldn't be without my woodburners.  When I leave, I often lay a fire for the next time I visit so I can just apply a match and away it goes.  Also with a woodburner you get to do manly things with chainsaws and axes if you want!

 On the To Do list is to install a heat exchanger, one of these days maybe.

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  • 2 weeks later...

Thanks everyone for the helpful advice.

Sorry it has been a while - been out of the country (and not for this reason unfortunately).

I appreciate the advice to stick with the French standard (do as they do and all that) and I am not planning to buck the trend. I suspect they are also pretty much the same anyway, given the close proximity(?)  Getting decent and trustworthy advice about the options available was all I was after. However, as I cannot do this very well just yet (negligible French, don't have any contacts, not over there most of the time, etc). I was hoping to accelerated the research process.

Maybe an even more basic question I still need to understand - namely what is the process to decide on what heating system to use? Could anyone help?

Are there anyone of the forum who is located in/near Bourganeuf and have some good tradesman that they would recommend?

Hung

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HQ,

The very first step in your decision making is dictated by your house usage, if a summer holiday home then you probably dont need CH at all, maybe a woodburner for aesthetic effect. If however its going to be a full time all year round house then its different.

Asumming full time, ie CH is definitely required ( its still not necessary, depends how rufty-tufty you are !!!).

First step. Accept the need for INSULATION, (Insulation + Insulation + Insulation). Insulation is effectively heating. It is probably the most cost effective thing you can install.

How much insulation and where? I hear you ask. The loft is always the traditional start point for very good reason - hot air rises. 200mm (8in) is, IMO, the minimum start point.

If you like crunching numbers (as I do) then calculate the heat loss from your uninsulated loft and then repeat using an insulated loft value at 200mm and 400mm thickness. Compare the answers and translate the figures to cost / kw using your electriity bill numbers - its an eye opener.

Next consider each room in turn, work out the heat required to maintain whatever temperature you feel you need. Conventionally this means 20 C in living rooms, 18C in bedrooms with an outside temp of -1 C (I know it gets colder than that but its convention). Dont forget that heat will pass through internal walls if there is a temperature differential. ie 20 C in one room with 18 C in the next room.

You an get all the U values etc on the net. Dont forget air changes, there are standard rates on the net.Also dont forget the floor.

You should end up with a heat requirement for each room, accept that it will not be necessarily accurate, the total is the heat input required for the whole house.

Now consider where you can realistically insulate. You may have good solid tiled floors downstairs which you dont want to disturb, so be it, you cant then (a) insulate the floor, (b) install UF heating.

Are you prepared to lose room volume by dry lining the walls, if not then you cant insulate there.

Do you intend changing windows, double glazing will make a difference but only if the windows are going to changed anyway, the benefits of retrofitting double glazing just for the glazing are IMO over rated (unless you have BIG windows)

Asumming you have now worked out where you can insulate, redo the calculations and end up with a total heat required.

Now its decision time. What type of system? wet or dry (circulating hot water or elecrical). If wet, what heating source? You may have Gaz de Ville available, is so that would be my choice. In the likely event that you havn't, then its LPG (GPL), oil, wood, ground source heat pump. Each has its own benefit and cost. I personally would not consider oil or GPL but thats my own choice.

I could go on but this post would be an epic. I am sure you get the point.

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We live in a big charentaise house that is cold every winter, we have oil fired radiators, they are all old except for one, this heats the room that it is in very well.  My question is could we clean out the existing radiators (somehow ) and therefor get a better heat source in the room, or would this be a waste of time and really we need to replace all the rads with new ones.

Thanks

 

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I'm presuming you mean traditional wet radiators heated by an oil boiler in which case yes it is very possible, and indeed advisable, to flush them out as if this has not been done recently or the system has been run for long periods without an inhibitor then they could be seriously clogged up.

You should be able to isolate each one by means of it's own taps, dismount it, and throughly flush it out, there are many common chemicals household which you could use to help in this process. Personally I would drain the system down and do them all in one hit then refill using the proper inhibitor, in UK I would use something like Fernox but unfortunately I don't know what the equivalent to this is in France.

If they are pretty ancient then you may gain some advantage in replacing them as new ones will likely be more efficient, something it seems you may have already discovered [;-)] 

 

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Realco make a range of additives, the brand is called 'Vulcan' . They do an additive for petit fuites (leaks) and what ernieY is talking about called 'Protection Preventive' (with an accent which I can't reproduce here). This is, I believe, both a corrosion inhibitor, and an antifreeze. It's available in the Bricos in the usual white 1L plastic bottles and also in 5 L sizes, and is used at a ratio of 1 L to 200 L of contents; though how you calculate the volume of the contents of your pipes, rads and boilers, heaven only knows!

Almost certainly other brands and ranges exist, which may well be every bit as good as the one mentioned above.

paul

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Thanks Steve!

That was a very helpful overview. Key message is to insulate.

The house will be for mixed use but primarily a summer home. If I don't put in some CH would there not be danger of burst pipes over the cold winter (it gets quite cold in Bourganeuf, I heard)? 

Sounds like I have to put my school cap back on. Where can I find the equation/formula/help on the caculation of the heating requirement?

The building is stone-built and rendered (personally I would prefer to keep the stone face but too late now I guess) with a basement cellar and some of the ground floor is parquet, with one tiled (old kitchen). I would prefer to have UFH but don't want to lose the parquet - is this a feasible solution. Obviously budget is a constraint but if the cost differential is not huge then it should certainly be a consideration.

HQ

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Check

http://www.diydata.com/planning/ch_design/sizing.php        Read ALL the assoiated pages, be careful with units, (watts vs btus etc)

We always isolate the water (and power) when leaving. Not had any burst pipes yet and we have been below -9 C. No guarantees.

If you want to keep the parquet then you cant UFH unless you take it up, do the necessary and then relay. Expensive IMO. Plus loss of headroom due to insulation, screed etc. Google "under floor heating" lots to learn about.

If you design using wet radiators, learn about radiator factors to apply to manufacturers figures to get reality!!!!!.

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For a holiday home then electric underfloor with internet control makes sense - at least you can control when away and put it on just before you arrive if needs be.

That said, of course its underfloor so the work may not warrant the return?

Marc

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I am looking at installing a Rossierre type solid fuel cooker in my Cave / kitchen which is the lowest part of the house and am thinking if I could duct warm air away from this to a heat pump I may be able to work a cheap ambient system just topped up by electric heating. I think that if I insulate very effectively this may just be enough allied with the log burner in the salle de vie
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What about exhaust waste heat use?  Run the exhaust through an insulated box and extract that heat to the air source heat pump.

I have no idea if this is feasible but it sounds testicle enough.....oops, that should read technical enough. Careful you dont drop the exhaust temp below the dew point though.

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If the cave/kitchen is the lowest point of the house, then the best bet is to probably run a steel conduit, right through and allow normal heat radiance to impart warmth to the house.

One instant problem of course, is if you extract heat from any solid fuel fire, then the chimney temp drops and causes poor combustion: which is why good Inox chimneys are now two part: inside for fumes and outside for lagging.

Adding the on-cost of electricity at day rate to the capital cost of the heat pump would not provide viability.

Good heat pumps are not cheap!

They are significantly cheaper in the USA and many merchants there will supply all the seperate bits necesssary.

 

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I believe that those heat exchangers, Mac are intended for hot air.

Interesting to see the operating temps of wood gasifying boilers and the fact they are all using a form of ceramic chamber for the main forced-air combustion chamber.

GS Heat Pumps need a considerably distributed collector area, whether they use boreholes or slinkies: a small localised much higher temp heat source wouldn't work too well.

 

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I have just been pricing up a wood gasifying boiler and found this site,

here

They say delivery throughout Europe.

The interesting point was the price of the Atmos 25GS worked out at E 2268 plus delivery. It seems a very reasonable price to me.

From a UK site it seems that the GS model is the one to go for, It seems it is is not normally available in UK from the Atmos dealers. I dont know the technical diferences - yet.

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I've spent hours on that site!

Not exactly the most technically informative place, is it ? I await with interest to see if you can find the difference between the various model suffixes, it defeated me.

The scary part is the total when you've added in the accumulator, the mixer thingy, and the delivery.

Still if the revenue every finish processing my tax rebate it might be a goer (in one hand, out the other!).

p
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