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Thermostat advice needed

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Thermostat advice needed
Hello everyone,

just registered on your forum today although I've been lurking around for quite some time now. I have difficulties reading in Slovenian though, but thanks to Google translate, I've managed to read some good stuff here. And I like the pictures, they don't say for nothing "A picture is worth a 1000 words", right?

I hope you don't mind me writing in English, as my Slovenian is, well, not so good. I am from Macedonia, but if I write in Macedonian, then you'll have difficulties understanding me, so.....

Last year, I was in the process of building a new house. I started in May, and moved in with my family in November. The house is about 240m2, and has a basement of 80m2 and about 160m2 of living quarters (a living room with a kitchen and a diner) on the first floor and 4 bedrooms on the upper floor. For heating and cooling, I chose an Aermec chiller with heat pump with 16kw of output heating power (model ANZ0507HA). The chiller is equipped with a Copeland scroll compressor. For backup, and during really cold days, I also have an electrical heater with capacity of 18kw, but this was rarely used (only when the temperature was really low, below -5C, the electrical heater was helping a bit, bringing the temperature back to the required 43degrees C, which I chose to be the operating temperature of the system. In those conditions, the chiller was able to heat the water to around 34-35 degrees C, before the electrical heater turned on. On the lower floor, I have 5 loops of UFH in the entry hallway, the kitchen and the diner (around 70m in length each), and one fancoil in the living room, and on the upper floor, I have 4 fancoils in the bedrooms, 1 medium sized radiator in the hall, and I also have 2 towelracks in the bathrooms on both floors. For the UFH, I have a 3-way mixing valve that reduced the water to 35 degrees C.

I was very pleased with the system and the way it performed this winter (my electricity bill was within the range I anticipated) and the system worked great. (during December-January, the temperature was mostly around 0 to -2C during the day, and -6 down to -14C (rarely though) during the night. In those conditions, I spent around 2500kwh of electricity total for the entire house. However, during the month of February, the compressor suddenly broke down, and I had to switch to my backup electric heater. The installer came to see and concluded that the compressor has failed and it needs to be replaced. As the chiller was still under warranty, they replaced the compressor at no charge. During that period until the compressor was to be replaced (about a month), I realized the difference between heating the house with heat pump as opposed to an electric heater. The bill for that period (March) was about 2,5 times bigger, and I am comparing the months of January and March, which is way warmer. When I asked why did the compressor fail in such short period of time (about 4 months of operation) I was told that although they had installed over 100 such units in the last couple of years, this was the first time they had a failed compressor. I hope they're telling the truth.

This was a rather long intro, and now for the initial reason for this thread

During the winter, I had the system up and running 24/7, which was not needed most of the times. For example, during the day my wife and I are at work, and our children are in kindergarten, so nobody is at home, but I had to keep the system working in order to have warm home when we return. Can I have some advice as to what kind of thermostat I can install in order to run the system more economically, and to be able to set certain parameters for the system to switch at certain periods in different modes. For example, I'd like to be able to reduce the water temperature during the night to, for example 35 degrees C, but then to be able to increase this temperature automatically 1 hour before I get up for work, and then, when we leave for work, the system switches off, and then back on before we return from work. I had this setup for my apartment couple of years ago, which was heated with an electric heater and radiators only, and this worked great, but I don't know how to do this with this system. The chiller has a micro processor built in, so it's not really convenient to run in the backyard to adjust the temperature daily, or even couple of times a day especially when outside temperatures are sub-zero. I have an option for a remote controller from the manufacturer, but it seems a bit overpriced (about 400 euros), and more importantly, it doesn't give me an option for timed programming, or even internet or telephone controlling. Ideally, I am looking for something that I can remotely control (either via telephone line, or even better, via internet). I looked at the Trane TZEMT400AB32MAA Remote Energy Management Thermostat, which runs for US $150, which combined with the Schlage Link System, would allow me to remotely control, but I am not sure whether this would work with my chiller. Once again, its an Aermec ANZ0507HA, of the Italian manufacturer Aermec.

I am also hooked to this English company called which have some really cool products in development, like AlertMe heating, but this product is not available yet. They also have AlertMe energy, which I think is the best thing since sliced bread (j/k of course) that they offer, unfortunately for UK customers only, that allows you to monitor the electricity in your house remotely, through the internet (either via their website, or via Google Power Monitor-another cool software from Google) and also, with smartplugs, to be able to switch on/off some of your appliances. Their products look very promising, so I will keep an eye on them.

Does anyone have a good advice on this matter, how can I make this work. I am sure that by smart controlling the power of the heat pump, I can save additional 10-20% on the electricity, and that's not bad.
If anyone has any questions about the system, I'll be glad to answer.



I will say few words about measuring the electricity usage. Since you are using the heat pump it is very likely that you have 3-phase electricity system. As far as I know power meters based on the induction coil (like AlertMe) are very unreliable and work only with 2-phase systems. Be careful about that. The best option would be to get the data directly from your main electricity meter. You should call to your electricity provider and ask whether they plan to provide remote access to the data in near future.

Regards, Crt
You are correct, I am using a 3-phase electricity, 380V.
Thank you for clarifying this. I read many articles about the AlertMe Energy product, but it never crossed my mind that it could not be applicable for a three-phase system. I am really interested in finding a way to monitor my electricity usage, for several reasons, not least of which is general awareness. My meter is a 2-tariff Iskra digital meter, installed 1 year ago. I am sure there's got to be a solution for this, I just haven't been to find it.

Long intro ;-)

I dont know if in Macedionia you have day- and night- electricity tariff. If the answer is yes the first thing you should focus is to run heat pump in lower (night) tariff. For this you need basic on/off timers - you must have some kind of storage units for heat; one for sure is UFH, 2nd should be water storage unit which I think you have since you mention electric heater.

Second - you mention heating water to 43°C which makes sense for radiators, but on the other hand you cool back down to 35°C for UFH. Fancoils also work perfectly well on same (low) temperature. In my opinion towelracks can use same water temperature as UFH.

This leaves you with only ONE medium sized radiator in the hall that acually needs higher temperature. Get a separate electric heater with hermostat for that one and run the whole system on LOW temperature. This is your biggest save!
Nebomgabiksal Napisal:Long intro ;-)

I dont know if in Macedionia you have day- and night- electricity tariff. If the answer is yes the first thing you should focus is to run heat pump in lower (night) tariff. For this you need basic on/off timers - you must have some kind of storage units for heat; one for sure is UFH, 2nd should be water storage unit which I think you have since you mention electric heater.

Second - you mention heating water to 43°C which makes sense for radiators, but on the other hand you cool back down to 35°C for UFH. Fancoils also work perfectly well on same (low) temperature. In my opinion towelracks can use same water temperature as UFH.

This leaves you with only ONE medium sized radiator in the hall that acually needs higher temperature. Get a separate electric heater with hermostat for that one and run the whole system on LOW temperature. This is your biggest save!

Yeas, we do have a 2-tariff electricity, tariff 1 (the more expensive one) which runs from 7h-13h and then from 16h-22h. In between (13h-16h and 22h-7h) we have tariff 2, which is half the price of tariff 1. Sunday, all day tariff 2. How is this in Slovenia, is it the same?

Back to your first suggestion, I do think this is an option, it's just not the one I had in mind. Instead of a simple ON/OFF timer, I can hook up a weekly one (about 35eu) and it'll do the job, and that's what I will do for the next winter season if I don't find what I'm looking for. But what kind of storage units are you referring to? I do not have any, the setup of my system is like this: the water in heated in the heat pump (there's a storage inside the heat pump, but I guess they all have, and that's not what you meant, right?) and when it leaves the heat pump, it goes through the electric heater (I think the English also use the word furnace), which has a thermostat, that basically checks the water temperature and if needed, turns on the electric heater. For example, I had the HP heat the water at 43 degrees C, and I had the electric heater thermostat at 40 degrees C. This way, when it was really cold, and the HP was unable to deliver a temperature of 43 degrees, the backup electric heater makes sure that I still have at least 40 degrees in the pipes. I was told this by my installer, but when i think about it now, I would definitely use an advice from an expert as to whether this is a good way of using the system or not.

For example, the HP is certified to deliver (some) heat with outside temp down to -15C, so I never ever turned it off during the winter, because the outside temp never went below -12. I do recall that in those low temperatures, the HP compressor was working his butt off to deliver warm water, but it often couldn't go over 32-33C. I had no problems with the heating of the house, as the backup electric heater was helping all the time (no saving money, but hey, I'm not complaining here) but I am thinking, is it possible that this contributed to the failure of my initial compressor (remember I told you that I had a failed compressor in Feb). My installer assures me that it couldn't be the reason, but somehow, I am not convinced. Any thoughts on this, huh?

So, when the water leaves the electric heater (furnace) it splits and one pipe goes towards the UFH (through the 3-way valve where's reduced to 35C) and the other part goes towards the fancoils and the radiator + 2 towelracks.

Now about your other suggestion, to run the entire system at 35C, and install an independent heater for the radiator. Well that idea about the radiator is great, and I am definitely going to do that for the next season. However, I am not really convinced about the fancoils running at 35C. I tried that setup once, but the outside temperature was bellow 0C, and I wasn't really happy with the performance of the fancoil in my living room (it was blowing a rather cold air, so I had to put a jacket on, run in the backyard and increase the temp back to 43C, which I have to do in the microprocessor located on the HP). This will probably work when outside temperatures are not yet sub-zero, and that's why, I am looking for a way to control the water temperature from the HP from inside my home, without running outside in the backyard. As I said, I have an option for a wired remote control from the manufacturer at 400 euros, but this does not offer any kind of remote access via the internet, nor does it offer a timer function.

Man, this volcanic ash disruption really leaves me with so much free time, and my posts are so long. They need to resume the air traffic back to normal, or I will continue with the long posts Big Grin

Have a good one guys,
First off I am not an installer or a guru. I learn as I go and I share my toughts ;-)
Keep this in ming reading my replies...

OK, your HP: ... er&sun=anz So, I have figured out that storage tank is included. Could not figure out the capacity tough ;-)

What I would do is connect UFH before the electric heater... If the HP can produce over 30°C in cold days you are safe. Then just use a weekly thermostat to use low tariff of electricit and dont' complicate your life too much

I hope g.o.dizzle will reply to this post also.
Hello there,
have you make some thoughts about turning your heating off completly in the high tariffs time?
So far i coud make out of your first post, you have a floor heating..
so you are warming up your concrete floor, which then gives the heat.
If you have some decent insulation arround your house walls, you should realy give it a try now, when the outside temps are still in the ranges, where you can see some difference when youre heating a house or not.
This thing mentioned above, works for me like a charm.
Im heating my concrete floor from 22 till 6 am, i'm putting in water (from 32-40 °C, depends from the outside temp) to have 22 deg. in the house.
And i have longer time intervals between higher and lower costs of el power than you.
On the last christmas, santa brought me a fireplace, which is now helping me to came over the peaks in chilling winter times, if the outside temp drops to let say - 15, like it did couple of times this year, i ran my heater (electric) on quite lower temperatures in compare to last winter, when the fireplace was not build .
If you have the place for it and you are not finihed yet, give it a go and try to position it so, that you can heat two rooms with it, either to place it in the wall so it sticks out on both sides of the wall or you put a chimney hose trough the wall and it heats the other room.
last season i ran my heating sistem about a month more, compared to this season, when the fireplace helped keeping the house warm. the wood for it costed me aprox. 80 € so far for this 3 and a half months, if i would run it on elecrtic power only, like last year, the bill for el. power will be some 300 higher.
Hope it helps.
kind regards!
ATC@LWSK Napisal:I also have an electrical heater with capacity of 18kw
Does it have some options, not to run it on full power?
I also have 18 kW heater for a little smaller house than yours and i come out with only 6 kw of power consumption, not turned it on all the time, when the heater is running (from 22 to 6), it turns on for 4-5 minutes, then it is turned off for 7-8, then on again.. the watter pump is running all the time.
Greetings to Makedonia!!
I'm a big fan of the documentary Šampioni iz Šutke, in case u heard of itSmileSmileSmile

About your heating setup..

As most of your house (the living quarters at least) is equipped with fan coils, reducing the temperature below 40+°C is not an option. The lower the inlet water temperature, the higher the fan speed of a fan coil, in order to achieve similar heating capacity. And you do not want high fan speed as it causes noise and discomfort.

I'm not sure if Airmec's main controller allows for power saving - temperature reduction function. If yes there is a solution with a simple timer, that signals the chiller's controller to switch to power saving mode that will reduce the heating temp. for 4°C e.g., which will save you approx. 10% energy due to higher efficiency.
If the controller does not have this function, you can simply set the indoor temperature a few degrees lower during the night and have the thermostat in the bedroom. For that, you can use very simple programmable thermostat, also available with wireless communication. This will not change the heating water temperature, however the chiller will run less in the night time.

Any other way, to heat the house in low tariff time period, to use buffer tank and heat it to higher temperature etc. is not suitable for you, as you have fan coil heating which is not exactly low temperature system, and it offers no accumulation, to keep you warm for hours after the heating stops.

Probably the best powersaving solution would be:
- ambient temperature controlled heating temp. - the lower the ambient temp., the higher the heating temp.
- multi-step electric heating - e.g. 3 steps of 6kW; 6kW at -5°C, 12kW at -10°C, heat pump off and 18kW electric heating below -15°C. Perhaps your heatpump shouldn't at all be running at -15°C or so. Should check the manual..

I hope this helps a bit, tomorrow i will pay more attention to this thread.. right now I'm really tired and can't continue to think any moreSmileSmileSmile
I read an article in which it was clearly mentioned that if you want to be smart then do these things s follows. By best proofreading service, the first was listening to the podcast of others. Podcasts are small documentary type videos. They help you in increasing your intelligence.
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