Heat pump decision

I

ipxl

Registered User
Messages
101
I've done a huge amount of reading and consulting with folks
(reading key posts on underfloor heating, heat pumps, other forums,
talking to users,installers,etc) and I'm at the point of trying to
finalise decision on whether to go with a ground source heatpump
with horizontal collector and underfloor heating in our new house
(2750sq ft, 2 floor block build house on 1acre).

When I try to do costings and payback calculations on heatpump
versus oil I can convince myself that it is worth it if we were
to choose underfloor regardless of the heat delivery method.
However, if push came to shove I'm not totally averse to putting
in standard panel rads in the rooms. In other words in my decision
process I looked at heatpumps first as a way of minimising the
rising costs associated with oil. I wasn't necessarily fixated on
underfloor heating at the outset. I only narrowed down on underfloor
because heat pumps confine our potential choice down to
underfloor heating delivery only.

So here is the what-if. My plan B is to install panel rads, a high
efficiency oil boiler, high spec thermostats including climate control
and zoned control of heating throughout house, pour excess funds
into maximising insulation (high insulative window glass, thicker
attic/roof insulation than normal,etc). Supplementing this with
solar heat collectors for domestic hot water (my bit for the
environment). Idea is to keep an eye on the alternative energy
sources with a possibility of switching out the oil boiler 5-7 yrs
down the road (or sooner) - I guess it is the natural instinct to
avoid being an early adopter. Also within budget using this
configuration would be to install a solid fuel/wood burning
stove in one of the main downstairs reception rooms.

Is there any logic to this. Completely illogical plan B ??
From anecdotal discussions it seems heat pumps are definitely
economical compared to oil when considering underfloor heating
is a must. However, I have this hunch that when you drop
back to conventional rads with oil and a decent efficiency
oil boiler & house insulation the economic arguments get
weaker especially considering the upward drag on ESB prices
by fossil fuel supply/demand.

Any critiques of my Plan B ?
Is this premature buyers remorse.. i.e last minute irrational concerns.?!

ipl
 
I also looked in great detail at the heat pump with under floor - but eventually I did not go down that route. I 'm now glad I didn't. Like you I was putting in the under-floor to suit the system. I know people with diagree, but as far as i'm concerned under-floor heating is not ideally suited to our climate. I have come to this conclusion base on the fact that my sister has it installed. You cannot beat flicking a switch and within 20 minutes the a room/house starts to heat up. Given that we can get all four seasons weather in a week in this country is a problem. Without out going into details I have heard some horror stories in relation to the heat pumps. I'm sure also there are people delighted with their systems.

I'm currently looking at a wood pellet &solar option, solar to heat the domestic hot water and wood pellet for central heating. The grants are now making these options attractive. I will be not spending more than 6000 on the boiler ( there are cheaper ones but I need to get more info on them)The only problem with the wood pellet is the extras , silos for storage for buying in bulk, augers , etc. I would agree they are new to the market here but have been proven in other countries ( all the boilers are imported as far as i know)
I believe that wood pellets will be available down south in the near future. I 'm going to use bags for the first year as hopefully more cheaper silos become available . If not I will Look A DIY job for the storage. There are risks but its looking like I will go with this system.


In relation to insulation, There is a trade-off that I'm starting so see whereby if you insulate too much - you can have air quality issue if you don’t ventilate. Of course conventional ventilation ( hole in the wall , vents in the windows) causes heats losses, the way round this is to install a ventilation/heat loss recovery system ( more money !!). Some where in between there is a happy medium. I know the purists will disagree.
 
I agree with your gut instinct that you don't want to be the guinea pig for geothermal. This is not suitable technology for heating in Ireland I beleive.

Regarding the heat pump shielding you from oil price costs...think again, electricity prices will rise with oil costs...which will be substantial.

I'm also against underfloor heating as its less efficient and more energy consuming by nature and also more difficult to regulate.

If you're thinking about a stove, these use alot of air to burn - your expensive heated air, try and use a system that does'nt rob you of your hot air as it could actually produce a negative heating effect - i.e. air intake from outside or boiler located in shed or garage

I would go for oil if wood pellet heating were not an option

Some other points;
Remove or block up open fires
Insulate well
don't be afraid to turn the thermostat down....its more healthy anyway!
 
IPXL,
Don't be afraid to be an early adopter. We're going with GHP with horizontal collector + underfloor on two floors. We've done the research and though there's some unknowns on balance we're confident we're making the right decision - a no brainer really I believe
 
Arasin,

I'm with you. I think that the argument for GHP stands up
well assuming you do an apples/apples comparison between
oil/underfloor and ghp/underfloor. It is just that I think the
payback interval for the combined underfloor, geothermal hp +
ground collector versus bogstandard oil fired rads doesn't
stack up as well. It seems to push the payback interval
a good bit way into the future. By that stage maybe the pump
may need to be replaced. I'm trying to stay the faith here
in geothermal it is just that some nagging questions/concerns
are popping up in my head before I sign the dotted line :) !

I'm worried about a potentially over-engineered solution
in an unproven climate. Feel free to continue to twist
my arm in one direction or another. In the end I'll make
a decision. Probably next week as it happens.
 
"....some research done..." So you shoud know that a groundsource heat pump is not a geothermal source of energy. Try the adress of the geothermal energy association for better research at htpp://iga.igg.cnr.it/index.php
Comparing an expensive and overdimensioned solar collector buried in the ground with geothermal energy is like comparing a matchstick with a nuclear power plant.
Do your research again.
 
Heinbloed,

I'm interested in your opinions on this for sure.

If I inadvertently used the term geothermal in one of my replies
I was probably clumsily perpetuating the misnomer which I know and
understand well by now. My research includes looking at posts
from you as well as others on this forum. Apologies if I misused
the term but I completely understand that ground source heat
pumps are *not* true geothermal. The trouble is the marketers
for GSHP have tried to overload the term geothermal...

The million dollar question though is ... could I be fooling
myself by buying into an overdimensioned/overengineered
system as opposed to just putting in a bunch of standard
rads (which I know have their issues such as less uniform
heat distribution in the room,etc). If I am willing to ditch
underfloor heating maybe I could put in oil fired rads and
a solar water heating system and say in 5 yrs time plan
to review the situation and possibly consider a switch to
some alternative biofuel/biomass/whatever heat source
which might be swapped in to replace the oil burner ...
 
ipxl,
What's the worst that can happen? You'll have a home heating solution that takes a few years to pay back. Best case scenario you'll have installed a proven technology widely used across the world ahead of the oil price meltdown and before the geo prices go through the roof and the grants dy up. DRIVE ON!
 
spud said:
I'm currently looking at a wood pellet &solar option, solar to heat the domestic hot water and wood pellet for central heating. The grants are now making these options attractive. I will be not spending more than 6000 on the boiler ( there are cheaper ones but I need to get more info on them)The only problem with the wood pellet is the extras , silos for storage for buying in bulk, augers , etc. I would agree they are new to the market here but have been proven in other countries ( all the boilers are imported as far as i know)
I believe that wood pellets will be available down south in the near future. I 'm going to use bags for the first year as hopefully more cheaper silos become available . If not I will Look A DIY job for the storage. There are risks but its looking like I will go with this system.
Click to expand...

What price did you get for the silo / auger? Easy to build one btw. Plywood will do the job
 
To ixpl:
Usually-in the very most cases, 99% of them- a heat exchanger supported by a low energy source like the soil is used to supply a low output temperature.
The smaller the temperature difference between the heat source and the output is the better the efficiency.
Going for standard sized radiators in a standard house (insulation/energydemand wise) supported by a standard heatpump will not be sufficient. Instead of hot radiators you would go then for a large surface energy spender like UFH or wall heating, if the wallet allows then go for the combination of the two.
But there are heatpumps since one or two years on the market delivering a working temperature of 65 degrees at a maximum.
But these cost about 50% extra - to buy. And they quickly exhaust the delivering media, you could end up in January with a frozen soil delivering nothing anymore until August or September.
Unless you extend the amount of soil tapped into by about twice the size of the standard.
That means extra costs for the heatpump and extra costs for the land purchase/installation of the heatexchanger.
And that would make the entire system uneconomical/more expensive then insulating the building. But there are exemptions as well. For example when the heatpump is used only for short times, the weekends. Or even better when the heatpump is used for cooling AND heating, lets say a relay station/factory/bakery etc. plus offices. But for a standard home it's a rather inefficient solution.
Remember that there is no pay back/amortisation as such for an item that needs permanent input of energy. But for an insulation meassure there is sooner or later a pay back achieved. Better call it an amortisation.
Only what is left over after reducing the demand of energy as far as possible should be "feeded" with a permanent/eternal input of capital/energy.
So first reduce the energy demand as far as possible. Then look out for a source of energy.
I could dig a bit deeper to get you some adresses of the high output heatpump manufacturers, those that deliver 65 degrees. But this temperature might not be sufficient, a badly insulated building might need an output of 80 dgrees.
Let me know if you're still interested in the adresses.
 
I am not looking at using any heatpump to heat panel/wall rads.
I'm looking at the following options.


1. GSHP (Nibe pump most likely which is suited for ufh working temperatures) , horizontal ground collector, domestic hot water
supplied as by product of the gshp heat pump.

2. Wood pellet boiler with either ufh or panel rads
(doubts on this -- see below)

3. A very decent (firebird or similar) condensing oil boiler
and conventional panel/wall rads. Oil boiler would be
a candidate for being displaced at a later time after
a review of alternatives in 3-4 years from now.
Logic being I've too many questions about wood pellet
boiler and wood pellet supply/storage in the Irish market.
I would prefer to see how that pans out even if it meant
I had a souvenir / hard to resell oil boiler on my hands
if I decided to make the switch a few years along the
line. Panel rads because even though heat delivered
isn't very uniform across room they deliver a more
bursty response to heating needs in the changeable
Irish climate. I'm assuming (could be wrong here) that
this might mean a lower monthly consumption of fuel
on average because ufh needs to run more continuously
in order to allow quicker warmup times.

I'm trying to critically examine option 3 at the moment.
I'd be prepared to invest in a good solar heating panel
system for hot water requirements as part of option 3.
I'd not have the funds to consider it with option 1 and
I'd feel I'd have a redundant investment in hot water
storage and generation if I bought solar + ground source
heat pump.

(thanks for the interesting info, btw about the newer heatpump technology
which delivers higher working temperatures. Its not relevant
within the options I'm considering though I think).
 
we have a NIBE Fighter 1110 gshp and underfloor heating installed - and wouldnt change it for the world - No radiators anywhere - we have a wood burning stove in our living area and an open fire in our sitting room - neither of which have been used as the temperature is controlled so well indiviudal room sensors as well as an external theromstat balance it out. Our first years electricity bill was 1400 euro - subtract 600-700 for lighting and that works out at approx 700 per year for heat and hot water - I estimate that we will pay for the additioanal cost of the HP in approx 5-6 years - possibly sooner as we are now looking at solar / wind to supplement. I would highly recommend ufh and gshp it worked out perfect for us.
 
Markbate,

Great to get some actual costs on this type of heating system. Couple of questions:
1. How big is your house?
2. Are you happy that the domestic hot water supply is hot enough and available on request?
3. Did you go with a horizontal collector and if so was the excavation and backfill a problem?
4. is the hp noisy and where did you locate it?

Much appreciated
 
markbate said:
we have a NIBE Fighter 1110 gshp and underfloor heating installed - and wouldnt change it for the world - No radiators anywhere - we have a wood burning stove in our living area and an open fire in our sitting room - neither of which have been used as the temperature is controlled so well indiviudal room sensors as well as an external theromstat balance it out. Our first years electricity bill was 1400 euro - subtract 600-700 for lighting and that works out at approx 700 per year for heat and hot water - I estimate that we will pay for the additioanal cost of the HP in approx 5-6 years - possibly sooner as we are now looking at solar / wind to supplement. I would highly recommend ufh and gshp it worked out perfect for us.
Click to expand...
Mark,

They are good figures. Do you mind me asking what the living floor
space area of the house is ? Is it timber frame or block cavity wall
construction.. and did you go beyond norms in terms of house
insulation measures ?

Why would you need solar or wind to supplement ?
I priced the GSHP and the problem with adding solar heating to the mix
was that I felt I'd have too much redundancy in the DHW heat
supply and I felt that I'd be over-specced to have both
installed.
 
ipxl said:
Mark,

They are good figures. Do you mind me asking what the living floor
space area of the house is ? Is it timber frame or block cavity wall
construction.. and did you go beyond norms in terms of house
insulation measures ?

Why would you need solar or wind to supplement ?
I priced the GSHP and the problem with adding solar heating to the mix
was that I felt I'd have too much redundancy in the DHW heat
supply and I felt that I'd be over-specced to have both
installed.
Click to expand...
 
2875 sq ft - block built nothing vast over the norm on insulation kingspan in cavity walls - we have concreate floors/ufh upstairs as well as downstairs - this helps with insulation/fire - one thing I probably would have done is triple glaze our windows. Windpower for powering the house/heatpump (electricity suppliment rather than heat) - I have a friend who has done this with a unit from - reducing his electricity bill substantially - we definatly dont need any more heat or hot water ;o) the hp produces everything we need whenever we need it - even with a full house. We have a bigger hot water tank than normal - we added an extra pump for pressure. We have 2 acres of land so had the room for horizontal collector (required 5 x 60m trenches x 3ft deep) which required a digger and a man for 4 days. Worth noting as this wasnt included in costs by our heating engineer!!

I would recommend puting your heatpump in a room/boiler house if you can afford it to eliminate any noise. Ours is in in our utility room which you do hear but isnt that bad. Good luck !
 
markbate said:
We have 2 acres of land so had the room for horizontal collector (required 5 x 60m trenches x 3ft deep) which required a digger and a man for 4 days. Worth noting as this wasnt included in costs by our heating engineer!!

I would recommend puting your heatpump in a room/boiler house if you can afford it to eliminate any noise. Ours is in in our utility room which you do hear but isnt that bad. Good luck !
Click to expand...

Is that 5 separate trenches of 60m length or are you saying
one trench which is 5m x 60m (300m^2).
If it is five trenches that is a lot of garden/land digging alright !

~ipl
 
ipxl said:
Is that 5 separate trenches of 60m length or are you saying
one trench which is 5m x 60m (300m^2).
If it is five trenches that is a lot of garden/land digging alright !

~ipl
Click to expand...

5 trenches, each 60m long, up and down each trench = 600M of collector tubing approx is what our engineer worked it out out at.
 
Thanks for that markbate.

Don't take this the wrong way but can you account for the fact
that you have joined askaboutmoney forums the same day
as you replied to my post about heatpump choices and have
only contributed to this thread.

I'm always wary of trolls on forums and while I am not calling
you out as one I need to be sure you are not touting for
a supplier. I have quite a sceptical view of the nascent
"green" energy suppliers in the Irish market. With SSIAs
maturing and a seemingly cash rich Irish consumer caught
up in the property bubble one has to be on guard for those
talking up various energy solutions.

Will we see you contribute to other threads on askaboutmoney?
Are you already contributing to threads on boards.ie, etc ?
PM me just to establish your bona fides.
 
i too am selfbuilding(blocklayer by trade) and am thinking of installing a heatpump and ufh.regards price i found that i can buy a swedish hp in poland alot cheaper than i can in ireland so may go that route,as for a previous point about the ground freezing if you take too much heat from it, as far as i know the pump will still supply heat to your house allbeit at a lower cop rating and remember heat is relative, the gas in your heatpump compressor will heat up at temp. well below freezing. my own view is to insulate well above the normal so you need less heating in your house.
 
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