Adding Oil Boiler to Heat Pump

rebellad

I have a Daikin Altherna Heat Pump with UFH on ground and first floor. House size is 2700 sq ft, It has been working well until the last couple of cold spells where the performance has dropped and I am finding it hard to keep the temp above 17 degrees at the moment. I have been considering 2 options to help heat the house. The first one is to add a multi fuel stove to the main living area of the house. This would at least ensure that the area where we spend most of our time is warm and wouldn't be entirely expensive. But this would only cover the main area The second option I am thinking of is putting in an oil bolier to work in association with the heat pump, I have seen it mentioned on here in some posts but not in great detail. My question is would it be difficult to install the boiler and connect it to the Heat Pump, also would anyone know what kind of expense this would be?? Thanks in advance

Condenser

Most good heat pumps have a facility for Bi-Valent heating. Which is basicly a contact that calls in a backup heater i.e oil burner, gas burner, immersion should they be required. You would usually be able to set a self determined set point (eg 0C) at which the unit would call in the back up system to assist with heating either in tandem with the unit or as a stand alone where the HP would drop out.

The bi-valent contacts should not be required except in instances where radiators are used as the heat distributor. I don't know if the Altherma units have these contacts. Ideally you would use a buffer tank where both the oil burner and HP could dissipate their heat.

OB would probably cost around €1400, Buffer tank (if you don't have one already) circ €1500, plus installation

newcavanman

We have an Aermec air to water heat pump . It broke down just before the cold spell began, and it took us nearly 2 weeks to get it fixed . We have recieved several recommendations, including from fitting an oil burner, to adding a second heat pump . I have since come across a plumber who seems to know what he is actualy talking about . He says, if you live inland, it is almost impossible for an air to water pump to work in these kind of temperatures . He says we need some sort of back up, which im only really starting to look in to now . We better find something, cause i cant take another

air

OP at 17 degrees you're probaby not much below your target temps in what are extreme ambient temperatures?
Have you any scope to easily improve insulation? If so it might solve the problem without adding any ongoing costs. Even if this isnt an option you might be better off just using some resistive electric heating for the few days a year or whatever that it's an issue.

holdfast

Most heat pumps would be sized to meet 80-90% of the heat demand. This is done to ensure the unit is not over-sized.

How long is the pump running ?
What temp are the heating controls set too ?
Does the house ever go over the 17 deg c or lose the heat over time?

putting in oil should not make any difference if the pump is sized right and working right.

rebellad

air wrote: »

OP at 17 degrees you're probaby not much below your target temps in what are extreme ambient temperatures?
Have you any scope to easily improve insulation? If so it might solve the problem without adding any ongoing costs. Even if this isnt an option you might be better off just using some resistive electric heating for the few days a year or whatever that it's an issue.

Well ideally we would like it up around 19-20 degrees in this weather but I don't really think that is possible. It's a new house (Approx 18 months old) with good insulation so there isn't probably much we could do on that side of things. I just don't think that the heat pump can cope with the temps we have had over the past few weeks so a secondary source seems to be the only way to guarantee the required temp.

rebellad

holdfast wrote: »

Most heat pumps would be sized to meet 80-90% of the heat demand. This is done to ensure the unit is not over-sized.

How long is the pump running ?
What temp are the heating controls set too ?
Does the house ever go over the 17 deg c or lose the heat over time?

putting in oil should not make any difference if the pump is sized right and working right.

Currently I have the heat pump on overnight for the reduced rate electricity and for 5 hours during the day. The temp is controlled by weather compensation except for the bedrooms which have individual stats that are set to 19 degrees currently. House has been over 17 degrees but not in the last few weeks!!

air

I think I would just get some oil filled electric radiators to help top up the heat during what statistically is unusually cold weather.
While I generally abhor direct electric heating I think yours is a case in which it makes sense, oil would be possiby be up to 3 times cheaper to run but as you're likely to use it for less than a month (?) a year, I don't think you could justify the capital installation (€3k ^) and any ongoing maintenance that the OB and store might require.

Condenser

rebellad wrote: »

Currently I have the heat pump on overnight for the reduced rate electricity and for 5 hours during the day. The temp is controlled by weather compensation except for the bedrooms which have individual stats that are set to 19 degrees currently. House has been over 17 degrees but not in the last few weeks!!

You need to let it run 24hrs. In the weather we've been having your efficiency could be down by as much as 50%. Turning it off after 5hrs will never let the house get up to temp. Also, you'll get more power from it during the day as temps are higher

holdfast

Well what is good insulation ? not to be critical but most peoples idea of what is required falls well sort of the basic regs.

good replies by air and condenser, I have a stove and put it on and let the doors open to heat the rest of the house during the day if required.It brings the temp by one to two degs depend on how long it runs. (the hse is 3500sq ft ) So if you have a fireplace it could be an option as well as the a/m replies by air and condenser

rebellad

Thanks for all the excellent replies guys, I may have to rethink my strategy here. I may look at the idea of a stove in the main living area as this wouldn't prove as much of an expense as the oil. Cheers

record

rebellad wrote: »

I have been considering 2 options to help heat the house. The first one is to add a multi fuel stove to the main living area of the house. This would at least ensure that the area where we spend most of our time is warm and wouldn't be entirely expensive. But this would only cover the main area The second option I am thinking of is putting in an oil bolier to work in association with the heat pump, I have seen it mentioned on here in some posts but not in great detail. My question is would it be difficult to install the boiler and connect it to the Heat Pump, also would anyone know what kind of expense this would be?? Thanks in advance

I had similar problems with a heatpump, so I got an oil boiler installed, which acts as a back-up when certain conditions are met (basically, when it gets really really cold). It does improve things no doubt. However, even with that, towards the end of the recent cold spell (with outside temps down to -15 / -16 each morning), the house was struggling to get to even 17 degrees.


As such, we are now going to get a multi-fuel burning stove installed. I think this will be the best way of dealing with the problem for the following reasons:

• It will bring the main living / kitchen area up to a good temperature and will probably throw some heat to connected rooms.
• This will then take strain off the main system, which now has much less space to heat up and therefore should be able to bring the rest of the house to the desired temperature.

It has the added benefit of being visually nice and cosy. Also, we find that, during spring / summer / autumn, the main system is off, but there could be a few nights where you could do with a bit of instant heat that an underfloor system is just not good at (there is about a 6-12 hour lag).