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Second Thoughts on Heating System

Kai

Hi,

Myself and my girlfriend are buying a house from my Parents and it is nearing completion, We had originally planned on putting in an Oil Range in the kitchen to heat the house but are now having second thoughts regarding the escalating fuel costs and have started looking at alternatives. The house has windows and external doors fitted but little else inside is complete apart from electrical wiring and chasing.

[1] Is it too late at this stage to change our mind regarding alternative heating.
[2] What options are open to us, ive been reading about Geo Thermal and we have our own Well which apparently is quite good but is too late as the Concrete floors are in.
[3] Wood pellet Stove is another option ive been reading about but is it a better solution for heating an entire house ?
[4] Has anyone installed Solar based systems ?
[5] What Timescale and Cost are we looking at for the various options.

Sorry loads of questions but id like to hear from people who have gone down the alternative route and what they would recommend.

:eek:

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Endymion

1) DOn't knoiw, how far are you allong. If a oil tank and oil boiler has been fitted then probably. Any change regardless of progress will cost you.

2) Its called a heat pump. Geo Thermal and all the other buzz words aside. They don't need to go under your house, in face that would be a bad idea. So your concrete floors might not have to come up. There a very good idea, but they thend to break down. Definitely wouldn't have it as my only source of heating. But a great idea for a duel heating system.

3) a boiler is a boiler. It's what determines how well you house will he heated. not the fuel.

5) all options are expensive and probably take awhile, with the heat pump taking ages.

tribesman

Carnivore wrote:

1) There a very good idea, but they thend to break down.

Says who? That's a bit of a sweeping statement. If anything a heatpump requires less maintenance than an oil boiler. We've had one a year and a half and have had absolutely no problems.

Carnivore wrote:

1) Definitely wouldn't have it as my only source of heating. But a great idea for a duel heating system.

We have a heat pump as the only source of heating for a 2500sq ft house and its excellent. It may not be suitable for the OP though because a heat pump works best with underfloor heating and if the floors are already in then UFH is not really an option.

A wood pellet stove may be an option but you'd have to think about how you'll feed it with pellets. I bet you'd rather not to be dragging bags of pellets in to the kitchen and spilling them into the stove. An boiler in an outside shed with a good size hopper that can store pellets for at least a few days seems a more attractive option if going the wood pellet route.

Kai

No Tank or Boiler or anything else is fitted, all thats in the house right now is some electrical wiring and some pipes for heating system but those can be easily moved.

Ok an external Wood pellet burner seems like a resonable idea, anyone have some links about them ?

Naux

Kai,

Search for woodpellet heating systems on the forum and It'll bring up some interesting older threads for you that might help you make a decision. Likewise with solar. Best of luck.

tribesman wrote:

We have a heat pump as the only source of heating for a 2500sq ft house and its excellent.

Hi Tribesman, I assume from your monikor that you are based around my neck of the woods. I am building a 2500sqft house in Galway next year and I'd like to get the lo-down on the heat pump system from someone that actually has it!!!

and not from hearsay etc. Questions would be electricity costs to run pump, soil type, supplier etc.

Tks

Naux

Endymion

tribesman wrote:

Says who? That's a bit of a sweeping statement. If anything a heatpump requires less maintenance than an oil boiler. We've had one a year and a half and have had absolutely no problems.

Says me. Me and that mechanical engineering lecturer I had for too years, that is. There allot less reliable then oil or gas boilers.

We have a heat pump as the only source of heating for a 2500sq ft house and its excellent. It may not be suitable for the OP though because a heat pump works best with underfloor heating and if the floors are already in then UFH is not really an option.

If they break down, their expensive to fix. Having a back up is a good idea. Also they might not be capable in every situation to provide enough heat, since they depend largely on the soil conditions and dept of each pump shaft.

Naux; Wrt electricity costs to run. With a decent heat pump for every kilowatt of electricity you put in you'll get about 2.5kw of heat. Thats not hersay btw, if you likes I'd do you out the maths behind that. But,of course, it all depends on how efficient your pump is, and how deep they go. I also Think there's some kind of grant scheme for people who invest in renewable.

zep

Actually most heat pumps these days will supply between 4 & 5kw of heat for every kw of elec, the tech as come on greatly in the last couple of years and are as reliable if not more so than oil/gas burners.
And as for the "says me" part, have you actually researched the reliability of every heat pump manufacturer on the planet to be able to back that statement up with proof?

Naux

Carnivore wrote:

Naux; Wrt electricity costs to run. With a decent heat pump for every kilowatt of electricity you put in you'll get about 2.5kw of heat. Thats not hersay btw, if you likes I'd do you out the maths behind that. But,of course, it all depends on how efficient your pump is, and how deep they go. I also Think there's some kind of grant scheme for people who invest in renewable.

1kw electricity = 2.5kw heat

So is that an efficient system? How much does 1kw of electricity cost?

Is the heat pump system efficient? A lot of people I know are sceptical about the payback period on these systems.

Also how much oil would it take to generate the equivalent 2.5kw of heat and how well would 2.5kw of heat, heat a 2500sqft house??????

Endymion

zep wrote:

Actually most heat pumps these days will supply between 4 & 5kw of heat for every kw of elec, the tech as come on greatly in the last couple of years and are as reliable if not more so than oil/gas burners.
And as for the "says me" part, have you actually researched the reliability of every heat pump manufacturer on the planet to be able to back that statement up with proof?

Right. I don't need to research every single heat pump in the world to have an informed opinion. Having studied mechanical engineering at third level, and having been told they are less reliable then other forms on heat generation by an expert in the field on thermodynamics, I can form an opinion. Technodlgy was never the problem. Heats pumps are relatively extremely complex when compared to oil or gas boilers, thats where the problem lies. You say that their more reliable then gas/oil boilers, (which btw have been in wide spread use for the last 100 maybe, years) whats your opinion based on.

secondly, the the statement "most heat pumps these days" doesn't make sense, since as you know, persumable, output is locations dependent. So meh, whats your figure based on. Mines based on standard examples.

Naux:
1) is that effecient?
Well, what do you think? If for every euro you gave me, I gave you 2 and half back, would you think it was good? Btw don't think that this means the heat pump has 250% effeciency, it might have maybe 85% - 90%. The pump isn't generating the heat, it's merely moving it from one place to another.

2) Look up your esb bill.

3) Yes, relatively speaking.

4) There a long term approach. They take awhile before they are value for money.

5) Oil boilers/gas boilers/every system that converts energy from one form to another are not 100% effecient. You're looking at at 30% - 40% effeciency, Meaning you wast allot of energy. So an oil boilder might be 35% effecienct. So you would need about 8kwatts worth of oil to generate 2.5kwatts of heat.

How do you see why people go to the expense of heat pumps?

6) 2.5kwatts is about what a small electric heater would put out. The amounth of energy needed to heat a house depends more on the matierials used to build it then the size of the house.

Naux

Carnivore wrote:

Naux:
1) is that effecient?
Well, what do you think? .

Ahhh........I dunno ..........thats why I was asking

Carnivore wrote:

2) Look up your esb bill..

I will I just don't have one on me..............I thought some knowledgable person might know.

Carnivore wrote:

3) Yes, relatively speaking...

Relative to oil they are efficient but.............you also said that they are relatively unreliable compared to oil boilers so a trade off I guess.

Carnivore wrote:

4) There a long term approach. They take awhile before they are value for money. ...

The way oil is going :eek: they might start being value for money sooner rather than later in comparison to oil systems.

Carnivore wrote:

6) 2.5kwatts is about what a small electric heater would put out. The amounth of energy needed to heat a house depends more on the matierials used to build it then the size of the house.

Overinsulate is what they say isn't it;)

Endymion

Relative to oil they are efficient but.............you also said that they are relatively unreliable compared to oil boilers so a trade off I guess.

more important then effeciency (well effeciency is important if you care about the environment) Is what do you get for what you put in. 1kw worth of oil will be less expensive then 1kw of electricity, you follow? Basically the OP would have to sit down and get a soil survey and all the rest, talk to an engineer and chrunch the numbers himself, before he knows if its a good deal or not.

To the Op, you don't need Under flour heating but it's a good approach. IF you're worried about the concrete floors, don't be. It goes in over them.

Overinsulate is what they say isn't it;)

Well, yea.

Macy

I wish that the pellet burners were a couple of years more advanced when we were building, as we probably would've gone for them. Never convinced about the heat pump - I felt that part of the projected payback was based on current electricity prices, and ours are so tied to oil prices anyway. And if you start getting into domestic wind turbines, you're increasing the costs further.

tribesman

Naux wrote:

Hi Tribesman, I assume from your monikor that you are based around my neck of the woods. I am building a 2500sqft house in Galway next year and I'd like to get the lo-down on the heat pump system from someone that actually has it!!! and not from hearsay etc. Questions would be electricity costs to run pump, soil type, supplier etc.
Naux

PM sent.

Endymion

Macy wrote:

I wish that the pellet burners were a couple of years more advanced when we were building, as we probably would've gone for them. Never convinced about the heat pump - I felt that part of the projected payback was based on current electricity prices, and ours are so tied to oil prices anyway. And if you start getting into domestic wind turbines, you're increasing the costs further.

A couple years back there was a company doing Combined heat and power based on the heat pump. basically Generated enough electricity to run itself, and heat the building. But that was a large scale project.

Mellor

Naux wrote:

1kw electricity = 2.5kw heat

So is that an efficient system? How much does 1kw of electricity cost? Is the heat pump system efficient? A lot of people I know are sceptical about the payback period on these systems.

Also how much oil would it take to generate the equivalent 2.5kw of heat and how well would 2.5kw of heat, heat a 2500sqft house??????

Yeah, it take 1 kw for a heat pump to move 2.5+ kw. Sounds good compared to alot of other heaters which can only generate heat from there fuel, and so can never get more than they put in.
But its worth pointing out that it takes 4 kw of energy to produce 1 kw of electricty. Just puts it in a different light. Heat pumps will be far greater when electricty production is cleaner. I would imagine in the future zero carbon systems will be able to produce enough energy for a heat pump, then they will be alot better.
As for the grants, they are available for heat pumps, wood burners/boilers and solar panels.

CJhaughey

Carnivore wrote:

Technodlgy was never the problem. Heats pumps are relatively extremely complex when compared to oil or gas boilers, thats where the problem lies.

A Heat pump is a fridge running in reverse, nothing complex about that.
Most fridges are very reliable, and so are most well designed heat pumps.

iplogger1

CJhaughey wrote:

A Heat pump is a fridge running in reverse, nothing complex about that.
Most fridges are very reliable, and so are most well designed heat pumps.

The physical principle employed in the heat exchange process is
more or less exactly the same as a refrigerator running in reverse but
...

We should also take into account that.
1. There is an additional circulation pump required to circulate the
brine or refrigerant gases through the heat collector system.

2. The scale of the system is way bigger than a fridge ... energy
input is orders of magnitude higher to meet the scale/capacity
requirements for space heating/dhw.

3. Depending on a lot of complex and delicately balance factors
including the soil conditions, climatic variations, collector area
(which ideally should be fully taken account of prior to design
and installation) the heat pump may at certain times need to
do a lot of work to satsify the heat requirements of the house.

On issue 1 - I pressed the installer/consultant of a very reputable
heat pump supplier on the lifetime of the various components in the
system. If I recall he said the circulation pump had a shorter lifetime
(poss 10yrs) compared to the main heat exchange pump. The main
heat pump is the most expensive part of the system. As an engineer
and even as a consumer I'm always critically aware of potential
points of failure in a system. For example, my air conditioning
compressor in my Megane failed after 3yrs and would have cost 700Euro
before vat to replace. I decided not to because of depreciation of
the car ... wasn't worth investing that to get the feature back.

On Issue 3: I've become really aware in recent weeks of the whole
issue of soil conditions and the suitability or not of horizontal
collectors. I'm still reasonably positive about putting in a heat pump
but our soil in Mid-North Connacht is too marginal in quality for me
(or installer) to be comfortable about putting in a horizontal collector.
I'm investigating bore hole. My concerns about compressor lifetime
still persist though!

I think there is more than a grain of truth in what Carnivore's
mech eng lecturer taught him even taking into account improvements
in heat pump technology.

~ipl

Endymion

CJhaughey wrote:

A Heat pump is a fridge running in reverse, nothing complex about that.
Most fridges are very reliable, and so are most well designed heat pumps.

A plane flys, a bird flys... ergo a plane is a bird... eer no.

iplogger1, summed it up nicely I think. Theres allot of components and factors working togther in a heat pump. Most of which are a) Complex,

expensive to replace.

CJhaughey

Well I take your point, with regard to a GSHP, BUT I would also point out that big GSHP installations are basically a custom job for every site and as such need to be sized correctly and installed correctly for each individual house.
If you have gone heavy on the insulation and installed a heat recovery ventilation unit it could be quite feasible to install an Air source Heat pump which is really more of an off the shelf type item than a GSHP, consequently many are made by manufacturers such as Panasonic, and as such are very reliable.
One thing is for sure a big liquid pump is going to cost money to run long term, and with electricity prices due to rise by 30% or so in the near future I would definately be looking at reducing the need for heating by Insulation and passive solar gain and HRV. Better to hold on to what you have than try and make more...