Advice

[Bryce1872]

My new house currently has a very large gas boiler (small car size) - the bills apparently match, in which case I need to decide on a replacement system. The house is 350 sq metres (3700 sq feet) - 17th century, very thick walls but not highly insulated by any means.

I am familiar with Pellet stoves and have 2 currently - my intention is to immediately purchase a ducted pellet stove (2 ducts) with independent fans. I will pipe these into the main rooms, dining, office, entry hall and living room via the service routes and cellar which already exist. The stove itself will be in the kitchen and I have the option of lowering, turning this fan off - or set to auto in this room.

A large part of the property does not require heating during the winter, so I reckon I can aim to heat 200 sq metres - bedrooms mostly and the radiators in the rooms already mentioned if required. (about 10 or 12 radiators)

I intend to run the new pellet ducting system and the gas system for the first year to measure the costs/consumption - the gas currently provides heating and hot water

My question is - would the recommendation be a pellet boiler (e.g. Sannover Grande 28KW) and simply replace like for like. Pellet delivery isn't too painful as they will deliver a pallet of 15kg bags in the driveway which can then be moved directly into the cellar via a hatch. But would this become a chore if the consumption is large (difficult to measure currently) and I get older

Is it worth having a large storage tank setup to heat first via the boiler and then feed the radiators? Or keep the existing gas setup - heat as required for periods (morning and night)

Is it worth heating the water by electricity so this setup can be used throughout the year and the boiler can be turned off?

I live in France where the winters aren't too cold and the heating is required for ~4 months of the year

Is an air-heat pump system worth considering or is the volume too large?

Any advice gratefully received

 

[EbS-P]

Lots of questions. What’s your budget? What are you saving by switching?

You have a boiler and pellets. A pellet boiler seems logical. Can you get bulk delivery into a hopper?

A heat pump water heater is the first thing I would add. We heat and cool 3000 sq ft down to almost -10c with an air source heatpump with electric backup. I would probably just start by adding a mini split heatpump in the largest space used year round if you went that way.

I just got a 10kw solar system with battery installed. I don’t see how heatpumps and solar not the future in green grass climates. Yes you need some auxiliary heat for the coldest 4-7 days of the year. Electrical heat is probably the cheapest.

All this said you could be using gobs of gas. Without know how much it’s and all your possible fuel prices it’s nearly impossible to say which one is the cheapest. With certainty I can say the cheapest option for the next 5 years is probably keep the gas boiler and air seal as best you can.

With the exception of the heatpump water heater every efficiency upgrade has at least a 10 year roi in our markets if you must buy the fuel. If you harvest your own firewood it can be much shorter

 

[Bryce1872]

Thanks for the reply - a number of the questions I don't really have an answer (just the bills are large as stated by the current owner) My current house we have pellet stoves, oil (central heating) and electricity tank for water (heating during the off peak period). We use the oil to heat the bedrooms mostly for a few hours in the evening - then again early morning. the rest of day you aren't in these rooms so why heat them - the living areas the 2 pellet stoves are ample.
I was looking at heat-pump water tanks - so interesting you recommend the same - this would mean no need for the gas 7-8 months a year as it's not used for cooking either and no doubt far more efficient than gas.
I guess budget will come down to what I'm paying out on the gas after I experience it for 1 winter at least. It's looks a very expensive gas boiler but I think it's 10 years old so there will come a point when it'll need to changed anyway.
I reckon we could store 2 pallets of pellets in the cellar - I'm just concerned whether living with a pellet boiler is a different ball game to 2 pellet stoves (approx 60 bags per winter) andt then we'll be stuck with it.
Regarding heat pumps for the heating, I'm just not familiar with the technology/performance - it would be ideal to get COP 1:3 and I would consider solar panels with battery backup like yourself. If I can be convined heat pump could do the job of heating it would potentially be a far simpler solution and not having to hump bags of pellets and order/store. Might have to look into this technology more.

 

[stoveliker]

Heat pumps certainly can do the job if heat pumps can do so in Maine and Minnesota.
The question is whether the heat pumps you can get in Europe can do the job. (I'm originating from two countries north of you, and there it's hard to find quiet and cold-weather heat pumps.)
Here in New York I have a minisplit heat pump that can easily heat my home starting from negative 15 to 12 C (5-10 F), and in MN and ME it's far colder.

A battery will be unlikely to make financially sense for heating; in winter sun exposure is lower but your kWh need for heating shoot up.
EbS-P lives in South Carolina, which is likely near Gibraltar lattitude.. - i.e. a lot farther south than you.

The best way would be to air seal as much as possible (not only windows but also attic!), and to insulate the attic and *outside of your thick stone walls* - that will make the walls like a thermal flywheel. I.e. you'd need quite some heat to heat the home up, but then it would take a long time for it to cool down as the walls keep radiating inward.
That allows a heat pulse and glide approach to be less annoying because temperature swings will be lower.

A lot depends on now many BTUs you need, and what their price is in your home.
So this winter keep an exact spreadsheet of outside temperature every day and night, gas usage, pellet usage etc. Using heat-degree days and the total BTUs (kWhs) used you can figure out what system would provide the amount of heat you need at the lowest cost.
You need data to make that decision. That should be this winter's job.

 

[Bryce1872]

Heat pumps certainly can do the job if heat pumps can do so in Maine and Minnesota.
The question is whether the heat pumps you can get in Europe can do the job. (I'm originating from two countries north of you, and there it's hard to find quiet and cold-weather heat pumps.)
Here in New York I have a minisplit heat pump that can easily heat my home starting from negative 15 to 12 C (5-10 F), and in MN and ME it's far colder.

A battery will be unlikely to make financially sense for heating; in winter sun exposure is lower but your kWh need for heating shoot up.
EbS-P lives in South Carolina, which is likely near Gibraltar lattitude.. - i.e. a lot farther south than you.

The best way would be to air seal as much as possible (not only windows but also attic!), and to insulate the attic and *outside of your thick stone walls* - that will make the walls like a thermal flywheel. I.e. you'd need quite some heat to heat the home up, but then it would take a long time for it to cool down as the walls keep radiating inward.
That allows a heat pulse and glide approach to be less annoying because temperature swings will be lower.

A lot depends on now many BTUs you need, and what their price is in your home.
So this winter keep an exact spreadsheet of outside temperature every day and night, gas usage, pellet usage etc. Using heat-degree days and the total BTUs (kWhs) used you can figure out what system would provide the amount of heat you need at the lowest cost.
You need data to make that decision. That should be this winter's job.

Totally agree - there's a lot that can be done to limit heat loss in the first place, closing window shutters, curtains across external doors etc very simple. Agreed the key will be monitoring the usage and températures closely to understand the house and how we use it. In some ways if the gas bills are as high as I've been told, then it'll make the decision to change easier.

More interesting info on heat-pump - we rarely drop below zero and only for a few days - our low is 36F

 

[sloeffle]

The question is whether the heat pumps you can get in Europe can do the job. (I'm originating from two countries north of you, and there it's hard to find quiet and cold-weather heat pumps.)

That's interesting that heat pump tech in Europe lags behind what we have in the U.S.. It's normally the other way around.

 

[Bryce1872]

That's interesting that heat pump tech in Europe lags behind what we have in the U.S.. It's normally the other way around.

UK love their Gas boilers - very small country with dense cities, so the majority of heating is gas. Even pellet stoves are not common in the UK but very common in Europe. Europe being larger and more countryside population and no mains gas outside large towns and cities, they have looked for other energy sources - mostly wood and oil. I guess similar to the US. Heat pumps are becoming more common but mostly due to the government incentives to swap

 

[stoveliker]

In The Netherlands, pellet stoves are not common and gas is literally in every home (including rural). The latter was cheap (we had our own gas, but they're stopping its production because of instabilities (earthquakes due to nat. gas extraction have inflicted a lot of damage to homes as they were not built to earthquake standards), and as a result that was basically the sole fuel for heating up to recently.

 

[EbS-P]

Those temps are great for air to air heatpump.

Cutting edge tech right now is air to water. There are heatpump systems that possibly could replace the boiler. I don’t want be the first person to install them. As service in the future could be difficult.

Totally agree - there's a lot that can be done to limit heat loss in the first place, closing window shutters, curtains across external doors etc very simple. Agreed the key will be monitoring the usage and températures closely to understand the house and how we use it. In some ways if the gas bills are as high as I've been told, then it'll make the decision to change easier.

More interesting info on heat-pump - we rarely drop below zero and only for a few days - our low is 36F

 

[sloeffle]

UK love their Gas boilers - very small country with dense cities, so the majority of heating is gas. Even pellet stoves are not common in the UK but very common in Europe. Europe being larger and more countryside population and no mains gas outside large towns and cities, they have looked for other energy sources - mostly wood and oil. I guess similar to the US. Heat pumps are becoming more common but mostly due to the government incentives to swap

Don't want to railroad your thread. I thought Europe was trying to get off of NG and oil because a lot of it comes from Russia ?

I live out in the county and surprisingly there's NG piped to some homes in my area. There's a creek that they were unable to drill under it so don't have it on my road. Most folks in my area heat with propane. Our local electric coop is incentivizing heat pumps with propane backup. Due to the high cost of oil( diesel ) vs propane I don't think a lot of folks use oil much anymore in my area. My house is all electric so I heat with a water-air HP, and a wood boiler.

 

[Bryce1872]

While I wait to fill in my spreadsheet with all my temperature and usage figures for the existing gas system , I'm going to get a couple of surveys done by the big suppliers in France (EDF / Engie) as they are really pushing the swap to heat pumps - no doubt their prices will be sky high but at least I will be able to get a better understanding of my property, any limitations etc. I hear a lot about changing radiators etc for heat-pump installations - the property has large cast iron original radiators - there's no way the wife will swap these out for a modern version.
I was also considering changing the water heating method from gas to Thermodynamic Water Heater and placing this in the cellar. That way I can use the gas for heating only and switch off in April to November. Any experience with these? https://www.airwell.com/fr/produits/eleo/

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[stoveliker]

Not personally but variations of this for hot water (shower etc) are used quite a bit here. Folks seem happy about them.

I don't know whether they can produce the number of BTUs you need for hot water radiative heating - surely they can but the question is whether it is straining this (still new) technology.

I am not an early adopter of new tech, but that's my personal approach.

 

[PassionForFire&Water]

I recommend you look into rebates or grants for pellet boiler installation.
It's my understanding that there are big incentives in France, but i don't know the details.
The major Austrian and German pellet boiler manufacturers are very active in France because of these incentives.
Replacing a large gas boiler with a bagged wood pellet option seems too much work.
There are bulk pellet delivery trucks in France.

Contact one of these:
Windhager France via https://www.bio-mass-terre.com/
Saelen France (Heizomat) - http://www.saelen-energie.fr