WoW, heat pumps are a sound proven technology, the issue with them causing huge bills is usually down to installers not setting them up correctly causing huge a huge draw on electricity demand, and as regards parts, well it depends on which you buy (I have been 3 weeks trying to get a component for a Sun oil burner!!)
have you changed from oil ch to calorgas
- Thread starter gailey
- Start date
Is it not a fact that the COP of air to water heat pumps diminishes during very cold air temperatures, as we had recently.
Discuss
Villa1 is absolutely correct. Air to water heat pumps will not operate and will shut down with temperatures below -10C. A back up heat source is definitely a must.
With regard to parts, any reputable manufacturer will have a decent back up service.
Me personally, I am not a lover of any type of heat pump. Too many crucial data must be adhered to for them to run efficiently. ∆T on the air side and the ∆T on the wet side are crucial. If installer does not allow for fluctuations in this, it will have expensive results. Danfoss make a decent one that has a built in automated controller to maximize the most efficient ∆T, but it is not released yet. Me thinks in a couple of months or so.
What the promoters of heat pumps do not highlight is this wee little electric 4kW element that kicks in when system is underperforming and this is often. This 4kW element is expensive to run and trying to heat a whole house.
Air to water heat pumps, in my opinion, are only suited to smaller properties and apartments.
More buyer be more educated than buyer beware!
Did I not suggest it with retaining the oil boiler as a back up! (me thinks I did)
A very good, and knowledgeable friend of mine sat me down recently and explained why, from setup some can cause huge esb bills, I would love to say I understood it all, but alas a lot went over my head and gone. He then went got and installed his own setup as he suggested and is happy as a pig in muck with it (wonder if he would tell me if was all gone wrong though!)
PS, his is a 5 bed detached house! But in truth I dont know enough about them to comment further, so will bow down to the 2 posters above.....
A very good, and knowledgeable friend of mine sat me down recently and explained why, from setup some can cause huge esb bills, I would love to say I understood it all, but alas a lot went over my head and gone. He then went got and installed his own setup as he suggested and is happy as a pig in muck with it (wonder if he would tell me if was all gone wrong though!)
PS, his is a 5 bed detached house! But in truth I dont know enough about them to comment further, so will bow down to the 2 posters above.....
You most certainly did.
I just find that unless the house is extremely well insulated, in that it can be heated by a candle, a heat pump cannot keep up with the heat loss. Fitted to a standard average insulated house of say 75w/m², it will not be able to keep up the losses. Remember, they are normally sized at circa 8kW, some 10 or 12. Getting into the 15kW range they are very expensive to run. A 10kW heat pump will have a 2.5kW motor, then when the 4kW element kicks in, it's now 6.5kW. Would you boil 3 kettles continuously for say 10 hours a day? (That's a modest consumption daily time)
When the outside ambient temperatures are warmer, then yes, it will not require the backup, but in winter, they are generally not and the back up will kick in a lot more than you think.
A 75w/m² heat loss property will require an input of approx 15kW + allowance for DWH. I understand that you do not have the rapid heat response requirement, but a radiator that is installed with a design average temperature of 60°C, now only getting 30°C (even on 10 hours/day), it will struggle to keep up with the loss of the room.
This is the what they are promoting; in that it can be retrofitted to heat radiators but I just don't buy it. I am open to be proven wrong, but it will have to be backed up with theory and calculations.
A good test would be to put an injection control valve set to 30°C to your flow pipe from an oil boiler and see if it will maintain the heat within the house. (You will also have to put a mixing valve between the flow and return before the ICV to protect the boiler).
W
Why-o-why??
Guest
well then,
If lpg is 7.1 kwh per litre and kerosene is 10.35kwh per litre and you have a 93- 95% effeceincy boiler , lpg will be over 30% less effecient even if cost of both were the same per litre??? am i getting this right??
If lpg is 7.1 kwh per litre and kerosene is 10.35kwh per litre and you have a 93- 95% effeceincy boiler , lpg will be over 30% less effecient even if cost of both were the same per litre??? am i getting this right??
Trilogy 1982
Registered User
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Kind of.
If both boilers have the same efficiencies then you will need around 30%less litres of oil than LPG to get the same quantity of heat.
If both fuels are the same price per litre then oil will be 30% less expensive to heat your home with BUT the LPG price should be lower to reflect the differences in calorific values.
Price the fuels in kWh and make your decision based on that.
Very true, Trilogy. Always base comparisons on kWh. No matter what the input is, the demand will be the same. Do your calculations based on how much it will cost to satisfy your demand in kWh.
Also take in consideration the efficiency of the boiler. If a particular boiler is only 70% efficient and another is 95%, then in addition to cost per kwh, there will be an additional saving in wastage or lack of it!
You don't want to be spending €1,000 on a fuel and burning a third of it up the flue.