Heat Pumps - post here.

graememk

https://www.boards.ie/discussion/comment/120081366#Comment_120081366

How much oil did you use in previous years? say 1L of oil = 8-9kWh of heat after losses.

During the cold snap, 70kWh say 60 to the heatpump could be 120-180kwh of heat.

I would allow it to do its thing, let it tick over.

Are you on a day night meter?

TheUnderfaker

Thanks for the response.

Don't really have any oil data as the oil boiler was busted when we bought the house. We had it replaced with the air to water heat pump at the earliest opportunity.

I don't have a day/night meter unfortunately. We're on a 24 hour meter. I've requested to be prioritized for smart meter installation though so fingers crossed that comes through soon and I can take advantage of some cheaper rates.

I'm not really in any doubt that I'm better off than I would be with oil anyway. Just trying to figure out how to fully optimise the system.

I'll leave it ticking over as you said and keep an eye on how consumption changes with the weather.

graememk

https://www.boards.ie/discussion/comment/120082345#Comment_120082345

Get a day night, the rates are usually cheaper on them anyway.

kabakuyu

https://www.boards.ie/discussion/comment/120082345#Comment_120082345

Did you have any other work done to the house at the time of the heat pump installation, was insulation upgraded?was an air tightness test carried out?you said you used the old radiators,are they suitable for a heat pump?did you get the grant?do you know the before and after BER ratings?

Sorry for all the questions, but I am considering a heat pump when my oil boiler gives up the ghost but all installers I talked to said other necessary works had to be carried out first, which adds considerably to the cost.

TheUnderfaker

Yes we had a good bit of additional work done. I got it all done through a one stop shop. I paid them the balance less the grants (we got 20k worth of grants altogether) and they applied for the grants on our behalf.

The insulation was upgraded. We got the cavity filled. I would have got the attic insulation improved too but we live in a dormer and it would have been costly to get it done through a contractor. I intend to improve the attic and sloped roof insulation myself this year.

Air tightness test was not carried out.

We got solar PV installed as well.

We got all windows and doors upgraded to A-rated.

The old radiators are suitable for heat pump and they are correctly sized. The company carrying out the work made sure of this.

My before BER rating was C1 and now it's A2.

Be careful going down the one stop shop route and get plenty of quotes if you do. The quotes varied wildly (we're talking many 10s of thousands) for the same work.

TheUnderfaker

Apologies if I've derailed this thread - feel free to DM me if you've more questions.

graememk

https://www.boards.ie/discussion/comment/120082893#Comment_120082893

By any chance do you have the heat loss calculations?

During the cold snap it was negative in some places all day, with some places getting to -10..

They sized your heatpump to need a 16kw, and say a cop of 3, Which would be about right for a flow of 50c (

Let's assume your heat loss per hour for the whole house is... 8kw. (Per hour) That's 192kWh of heat energy. Cop of 3 brings down the electric needed to move the heat to 64kWh..

Does your heat pump have any stats?

kabakuyu

https://www.boards.ie/discussion/comment/120082895#Comment_120082895

Thank you, you have been most helpful, I have carried out some upgrades over the past 3 years(solar, windows,attic insulation,TRVs)I am now looking to having the cavity filled in the next few weeks,My oil boiler is relatively new(8 years) and is a high efficiency condensing type but I need to look to the HP in the future.

simpsimp

Quick question - with our air to water heat pump - we have a 4 zone system - 3 zones on ground floor with UFH, 1 zone on upper floor with rads.

When installed, the HP people were expecting digital stats (Heat Miser) - but the plumbers had installed analogue stats.

Just looking to manage HP energy consumption, would it be a cost effective society to switch to digital - and then time some rooms to adjust required temperature by time of day?

Or is it just as good to keep each zone at same temp 24/7?

Nelbert

Depends on wiring on the analogue stats. Most stats are just a live, neutral and a switched live back to call for heat. If the that's the case then you can go with digital stats.

I've the heatmiser neo hub with 9 zones (3 UFH and 6 rads) controlled with neoStats on each zone. Works well, connects via homekit and to home assistant no problem.

I've timers set on them to adjust set temp up and down during the day but once late Feb / March hits there's not many calls for heat and the heat pump just does the hot water.

MicktheMan

https://www.boards.ie/discussion/comment/120082893#Comment_120082893

"we live in a dormer" "Air tightness test was not carried out."

Your best bet is to have the test done. Address the issues found. These can be really significant in a dormer.

TheUnderfaker

https://www.boards.ie/discussion/comment/120083025#Comment_120083025

1.827 W/(K·m2) is the HLI on my BER... Not really sure what that means to be perfectly honest!

Heat pump does have stats, but they're quite difficult to read. Energy input and output are given in a bar chart hourly over the course of the day so it's hard to tell exact numbers on it. The "input" bars this week are lower than they were last week, and the "output" bars are higher than they were last week so I've definitely increased my COP since switching over to the weather dependent mode.

https://www.boards.ie/discussion/comment/120083937#Comment_120083937

Will certainly get that done this year. I plan to replace pretty much the entire ceiling upstairs to get some insulation boarding between the rafters (fiberglass in there now) so I'll get an air tightness test done beforehand.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120087528#Comment_120087528

If your heat pump is showing a higher COP then at first glance you should be running more efficiently

In general it's better to run heat pumps for longer at a lower temperature, the closer the outside temp is to the water temp the more efficient

If you look up the spec sheet for your heat pump you'll see a whole load of COP values, generally the best one is when the water temp is 35C and the outside temp is something like 20C

If you're on a 24 hour meter then there's no advantage to trying to load the system more at night

I would generally advise against a smart meter at the moment, rates are terrible. It might be worth getting a day night meter depending on your usage, but it's kind of up to you

I would double check to see if an air tightness test was done, I'm fairly certain it's part of the BER assessment anyway

the_amazing_raisin

So as an experiment I've been trying to shift some of my heating usage to night rates to save some money

I've only normal rads and a small buffer, so my only real thermal store is the house itself

I can only do timed temperature control downstairs, upstairs has to be set using a manual thermostat

I would normally have the thermostats set to 19C downstairs and 15C upstairs (in reality 20C, turns out the thermostat isn't accurate)

I've been setting the downstairs heating to boost to 21C from midnight to 7am every night. The idea is it'll warm up the house and the entire insulated space would essentially soak up heat for the night

It also mean I don't get boiled as much during the night because the house seems to heat up more slowly

Unfortunately I don't have any good ways of measuring the heat pump usage other than the graph from the MyEnergi app

It does looks like more of the usage is happening at night. I've also noticed the house will hold the heat during the day and it doesn't seem to require heating until the evening. I can even crack the windows for a bit to air the place and it doesn't cause the temperature to plummet

I'll check the meter reading towards the end of the month, I'm normally around 45% night rate usage, I'm hoping this change will push it above 50%

ColemanY2K

https://www.boards.ie/discussion/comment/120087528#Comment_120087528

i recommend covering the upstairs ceiling and walls with airtight membrane after the insulation has been fitted. if you want to save a few bob on the best stuff i recommend buying intello plus online from germany. i recently bought a load of it to cover 194m2 of ceiling area for around 1200 euro. now that included the airtight tape, mastic and paint as well but it saved me the guts of 500+ euro. pm me if you want the details.

ECO_Mental

https://www.boards.ie/discussion/comment/120087887#Comment_120087887

Yeah I thought about that myself but you probably need to know will actually need heat the following day...what happens if the next day is nice and sunny and you get solar gain then you over heated you house for no real need.

You could probably do it alright through through an automation in Home Assistant where you get the next 24hr forecast (which would be accurate enough) to predict if you need heating the next day. Then you could ramp up the heat.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120089587#Comment_120089587

Well I can do a fairly coarse method by just turning the downstairs back to 19C when the weather warms up in spring, but yeah some sort of look ahead weather compensation would be ideal

The jury is still out as to whether it's having the desired effect on electricity usage. I'll be taking a meter reading today and in a month which should give me a general comparison of the two methods

ECO_Mental

https://www.boards.ie/discussion/comment/120090525#Comment_120090525

The only way is to evaluate it is do regression analysis on your heating use....sounds more complicated than it is but what you need to do is set up a baseline of your energy usage so you can predict what at any given day how how much heating you should be using. This way over time you can plot actual over baseline to see if you are getting more efficient.

Get your Heat pump daily usage in kWh and then get the heating degree days for you particular location

Heating & Cooling Degree Days – Free Worldwide Data Calculation

Plot one vs the other using a scatter graph and then get a best fit "linear" line for the data you need the graph to show the R value and the equation of the line. The R value is how well the data fits, this needs to be over 0.8 to be of any use. Basically for my data below I have only 0.6 which means that cold days don't really drive the energy use in my house as my heat pump does hot water as well and we have showers during the summer as well...

But for example if you boiler is only doing the space heating this R value could be 0.8 or 0.9 so you could predict you energy usage to about 80 or 90% accuracy based on how cold it is based on the previous years energy use. You need to do this for a calendar year to get your baseline.

You use the formula to predict your energy use, so for a given day use the formula (x =heating degree day number) and this gives you Y = estimated energy use base on how cold it was. You can then plot actual vs predicted to see if you were over or under. If you make a change in your heating practices and set point you might be able to see it.

Big factories use this to manage energy usage to check to see if they are using more energy or less energy based on for example the number of widgets they produce. How this works for a domestic house is a bit debatable because domestic houses have big swings in energy consumption and little things can have a big effect.

eamo_c

Hi, I'm getting a heat pump installed in the next few months - but struggling to find out costs in getting gas turned off.

Gas networks Ireland can remove the gas altogether for €827; but advised me to contact my provider (electric Ireland) to enquire about getting the meter disconnected and pipes capped - as this should be less.

Struggling to get an answer out of Electric Ireland - anyone got any guide on price of this ?

babelfish1990

https://www.boards.ie/discussion/comment/120102150#Comment_120102150

I went through this process a few months ago - also with Electric Ireland for gas. They told it it was going to cost around €80 to get the gas meter locked (I can't remember the exact amount). However, looking back at my bills - they don't appear to have charged me anything yet? They also said that I would have to pay €50 penalty for breaking my dual-fuel contract early. I expect that this will be charged in a couple of months when the original contract was due to end - maybe I will also pay for the meter locking at this time? My gas bills have gone to zero since the meter was locked. Gas Networks Ireland also gave me the higher cost for getting the meter removed - but they said this was unnecessary unless I wanted to reclaim the space where it is located. (eg you might want to do this if you were building an extension).

ConorC1

Is there a recommended temperature setting for UFH water when it is also used to heat radiators on upper floors?

Nelbert

It would depend on the what the floor structure and floor covering is specced for.

You may also have a mixer valve to bring the UFH temp down if your rad temp needs to be higher. You'd need to check with your installer about what's suitable.

BoardsMember

On UFH, I've done a lot of reading on what materials. Tiles obviously our perform everything. Would it be mad to lay engineered wood if an acceptable tile alternative could be found? I know a little off-topic, apologies.

DC999

https://www.boards.ie/discussion/comment/120119214#Comment_120119214

You floor’s main purpose is as a floor, which includes the look and feel ye want in the room. And the secondary purpose here is to radiate the UFH.

My folks got floor tiles years ago and without UFH, they are freezing cold. They actually radiate out the cold. And lethal when they are wet. Worth thinking about if there will be young kids or older people in the house (even with a small water spill, I don’t just mean after mopping it all). So I’d suggest pick the material that best suits ye. 

graememk

https://www.boards.ie/discussion/comment/120119214#Comment_120119214

It will work, heat will get out eventually but will be a lot less responsive.

A good underlay will make a cheap laminate feel good, whereas a cheap underlay will make a expensive floor feel cheap.

It's like putting a coat over a radiator. It will work.. eventually.

MENACE2010

https://www.boards.ie/discussion/comment/120063427#Comment_120063427

Hi I tried the 'always' on and was told do not use thermostats as the heat pump will do its thing..... guess what .. leckky bill through the roof, at this point i have a double approach , thermostats and the heating is 'blocked for 8 hours ( 8 - 16) and come on in the evening with the most of the heating being generated on night mode ( 11pm - 8 am) and hot water is generated around the same time . I have a more manageable bill at this point. The annoying part for me is that ( 8 yrs ago ) I was a novice and they did not install an internal thermostat for the heat pump.. now the pump works off the return loop temperature and the delivery and outside temperature , with a bit of sunshine .. the house shoots through to 23 degrees.. anyway.. moral of the story . get as much info you can get and experiment..

ConorC1

https://www.boards.ie/discussion/comment/120119214#Comment_120119214

Tiles cover about 2/3's of the ground floor and Engineered wood the other 1/3. The problem is the stat (just one on the ground floor) is in the room with the engineered wood so there is a serious imbalance in room temperatures when it's calling for heat for a few hours

Nelbert

At the moment you have one stat but have you multiple runs with actuators on UFH manifold? Could add another stat if so.

Ive 6 actuators with 4 stats on my UFH mainfold. 1 of them controls 3 of the actuators.

ConorC1

https://www.boards.ie/discussion/comment/120121303#Comment_120121303

Correct. 1 stat and 4 actuators. Is there much to adding an additional stat?

Nelbert

Depends - have you a pic of the wiring at the actuator end?

Mine there's a wiring Centre all the stats go back to. Each zone the switched live from the stat calls for heat (as you'd expect) and also power to the relevent actuator/s.

Essentially you need a stat for the new zone (you'll need to figure out which actuator controls where but hopefully they are labelled).

This could potentially be a wireless thermostat and a relay receiving the wireless to call for heat and open the relevant actuator.

The stat is really just a temperature controlled switch but some stats are 12v, mine are 230v, others are wireless to the room with the switching controlled by a relay at the heat source and manifold (nest thermostats work this way).