We did extensive renovations to our maisonette apartment in 2020 (lower floor, flooring, moved kitchen into living room in open plan, remodelled reduit, converted old kitchen into a separate bedroom, installed a new kitchen) and a complete ground-up renovation of our bathrooms (2 full bathrooms + 1 guest toilet) in 2022/2023.
My wife project managed both renovations. The cost estimation given by a planning/architecting agency for the 1st renovation was approx. 143 KCHF and we managed to get it done in approx. 65 KCHF. For the 2nd renovation, the professional estimation was approx. 123 KCHF and we managed to get it done in approx. 83 KCHF.
Since we live in the Basel area, for the 1st renovation, we went thru a French company as the main designer/contractor and they in turn brought in their Basel based sub-contractors. For the 2nd renovation, we went directly to the previous Basel sub-contractors.
The 1st renovation was very stressful as it was done during the height of Covid and we were also living in the apartment at the same time (never again). The 2nd renovation was comparatively less stressful as we mainly went with professional tradesmen on account of bathroom/toilets.
For the flooring in the 1st renovation, we went with water resistant laminate (Meister LL250S) and are very happy with the result. The aesthetic is closer to natural parquet but we dont bat an eyelid if any of our kids spills suff while playing, running about, etc.
I’m planning to replace my building’s oil heating system with an air-to-water heat pump, add external wall insulation, and replace the original glazing (early 1990s).
I would appreciate any advice, best practices, or feedback from those with experience in this type of energy renovation. Thanks in advance !
It is not possible to give any tipps without further informations about your house.
How much Oil do you use per year for how much m2 space? How is the house build? Material of the walls and insulation? Is the roof insulated?
About the Heat Pump: make sure become an expert yourself. Many „heating contractor“ Will sell you a too big heatpump which costs much, is less efficient and will brake down early, combined with efficiency killer like buffer tank etc.
If you are german speaking I recommend to invest few hours reading on energiesparhaus.at
It should be distinguished between two scenarions:
Buffer directly after the heatpump.
Pipe with warm heating (Vorlauf in german) water goes in the buffer and from there on in your heating system. Most buffer tanks have few 100l capacity. A heatpump brings a water flow at least of 1500-1800l/min.
That means a normal buffer tanks is not really able to store signifikant of heat coming from the Heatpump. The high flow mixes the water entirely and the heatpump will do many restarts caused by that. restarts are bad, the machine will break down earlier and each restarts costs a lot of energy.
Additionally you need a second pump which circulates the water from the buffer through your heating pipes.
Buffer on the cold side before water goes back in the heat pump
With a air water heatpump you need enough of water to di a de-icing if necessary. If your house has radiators and no floor heating you might need more a additional tank to put enough water in your system. This is also called „Pufferspeicher“ bus has only the function of adding more water volume to your system. There are no impacts on the efficiency.
A heatpump is a other mechanism compared to oil or wood heating. Oil and wood are burned. A fire has a minimum energy coming out of it. sure they also can be regulated, but for air quality etc it is best to burn at maximum power. There is a big risk for excess energy, which you can store in a big buffer tank (often some xm3 large).
A heatpump on the other side can deliver without problem a variable amount of energy.
Many „heating installation company“ does not respect that. They have been educated on oil and wood heating systems. In general I suggest to look for a company having people employed coming from the „Kältetechnik“/refrigeration industry. They have a deep understandig of a heatpumps concept.
If you plan to replace an old heating system you should start at least one year earlier:
open all the termostats in your house. Adapt the heating curve until the climate is right for you. Probably you need to play around a bit. The room where you like it to have the warmest sets the limit (often bathroom) afterwards reduce the flow in the other rooms with the thermostats)
attach some shelly sensors on the warm and cold side of your heating system. And a third sensor to capture outside temperature. Homeassistant can be used to collect the date. This will tell you what „Vorlauftemperatur“ you need depending on outside temperature. Maybe there are other ways to collect this data.
Note as precisely as possible how many fuel is used. several times in winter. Or better install a heat energy meter (wärmemengenzähler)
If you have this data you mow what your building needs as heating energy. If you do not have that you need to work with „your best guess“ which probably includes some reserve. It mostly costs time and a few 100 bucks for some shelly equipment.
I am limited in my english and this is a complex topic. I hope what I wrote is understandable. And sorry for this long post, I might be a bit involved in the topic - I hope the read was worth your time.
OMG, your post just showed me that what I think I don’t know about the heating system in my house is just a tip of the iceberg . Thank you!
I think that what I have is the 2nd case:
I have radiators instead of floor heating
There is only one pipe going to the smaller tank which goes through cold water (blue) measurement thingy
It’s called Pufferspeicher and has capacity of 282l
I thought it increases efficiency…
For @kawansky ‘s question: we did huge renovation, including changing from oil to air-to-water heatpump. From what I know, it won’t be as efficient with radiators as with floor heating. Plus you may anyway have to exchange radiators for the ones with big heating surface (@newhere please correct me if I’m wrong or use wrong wording). Don’t forget about possible subventions, but I guess it will be 10% of the investment maximum, possibly less. Finally, we bought a house and started the renovation before moving in. So I don’t know how it worked with oil heating, but according to previous owner told me, I think we now pay more for energy than he was paying for the oil… So I would think also about doing photovoltaic panels at the same time. In 2024 we have used > 8k kWh.
With radiators you need a bit a higher temperature in the system compared to floor heating. Each degree Kelvin between source and sink lowers efficiency. Thats why a brine-water heatpump is more efficient than air-water one.
Subventions in Kt BE are 10k for a brine-water heatpump. Since I chose the DIY way instead of drilling (total costs 40k instead of >80k (best all-incl-offer I got)) it was 25% for my case.
If you like @baldur you can tell me the kwh heat produced by your pump or the JAZ. You should see them in the interface of your pump. I am able to judge if it has a good efficiency. If not I can you direct to some (open-)source of knowledge to find out how to improve your system. Very often simpel changes in the settings can help you.
8000 kwh sounds a lot if you calculate with a (rather bad) JAZ of 2.5.
That would be amazing! I’ve quickly checked, but I don’t see any stats/information about energy produced etc. I have a CTC pump, not sure it matters. Anyway, I guess the others are not interested in efficiency of my installation, but if you can share the links to get more knowledge/tips, I guess anyone could benefit from that .
I can try to summarize a few to-do’s when chosing a heat pump. I will post links to external ressources. I hope that is ok, since the other forum has nothing to do with finances.
Know your energy need during the heating period. Note eg. once a week or twice a month how much oil/ pellets/gas etc was used. You can convert this into kwh,
Use the Hottinger formula there is a briefexplanation here. briefly:
kW = HWB (IT - NAT) / (HGT h) HWB (in kwh) = Liter/kg consumed energy source x energy density x heating efficiency = kwh
for oil it would be liter oil x 10 x 0.85 (depending on the age of you burner) IT-NAT = difference inside temperature (eg. 22°C) to min outside temperature (likke -10°C for swiss central) HGT: you can check online HEV h = running hours per day: check on your old heating system. Very often this is 18h/day
This will allow you to have a pretty accurate idea how much kW power your system needs to have. If the kW power of the installation someone wants to sell you, be sceptical
For air-water heatpump, very important: a modern heatpump delivery a variable amount of energy depending on the outside temeprature. Each model has a specific performance curve, you can find it in the data sheet from the manufacturer. Make sure the performance curve fits your buildings needs. This and pojnt 2 should be the main arguments to chose a heatpump. Do not limit yourself on the brands your prefered installation company has under contract. more informations about this step in this thread
You probably do not need a buffer when you have floor heating. with radiator only to enhance the volume, in the “rücklauf”.
Check if your heatpump has a coolant which fits future regulations. GWP<2500 and not more than 3kg would be good. For Air heatpump there is now a good selection of models with propan (R290), which is the best choice.
If possible get a brine-water heatpump if you have a garden, check the concept of “Ringgrabenkollektor”
I am not an expert in this field. I educated myself only for my specific case, so I wont be able to give good advice for each specific situation. But I have found during 3 years of research, that many installation company do not respect these basic principles. There is a big possibility, that they install a too big model, with to many things like buffer etc. This increases buying costs, reduces efficiency and impacts how long your new machine will work. After discovering this I talked to an scientific expert in that field. He confirmed my opinion.
And to be fair to all companies: I am certain there are companies doing a perfect job out there. Altought I had 5 different one on place and didn’t found any of them..
Thanks for your reply. Not sure how much Bauwerk parquet has changed nor when you had yours put in but if you remember what model and finish you have I’d appreciate it. Oil or B protect?
I’ve had samples brought to my home and it’s very different from what I saw in the showroom. My installer also said that it’s too big of a difference. He alsi mentioned that although Bauwerk is a still a good product things have changed over the years with the company. They rely a bit too much on their name and the quality has maybe slipped a bit but the price hasn’t. These are his words not mine. He has been a Bauwerk partner for a long time.
I’m aware that each batch can and will have differences but this looks like a completely different floor and color. Anyway if you by chance remember which model you have please give me a shout
Thanks for your reply. Finding the tradesmen has become quite a project. I get replies that they would like to do the work and then don’t reply for weeks. When they do reply after I ask again they said they’re on Holiday and will get back after a week. It’s turned into three weeks. I do realize it’s summer holiday but soon it will be another holiday. Does everything shut down in August? Do Tradesmen often over book or is it just harder to get them to do private homes instead of new buildings? Im having a hard time understanding why it’s been so difficult.
My parquet guy didn’t even talk about products, but rather things like different woods, sizes, how “clean” the surface will look, how it’s treated and oiled or the layout. Good chance they produce it themselves instead of buying from a bigger vendor, but still had plenty of choice in their showroom.
Many tradesmen are pretty small and it makes sense to me they need to plan ahead and prefer bigger projects over small ones In big projects, they’d have a fix time window to get the work done, yet might face delays caused by others.
The small ones don’t have own sales or admin people, but the owner or a family member is doing it while not at a customer site or in the workshop to get things done.
You could give it a positive spin, that they’re passionate about their work and less about office and show room activities
I got the small Formpark and made herringbone pattern. (only bought the product and did the work myself) The look is as expected, i chose „ruhig“ and only oli, not the special surface.
We still love it.
What does your Guy mean by quality? I am always sceptical when a reseller of different brands talks one down without beeign specific. Depending on the size of the company they get easily 30-50% margin on the product. Even if you go by yourself to the showroom and the team there does all the consulting.
But I am not an expert, to me it looks good, I like european origin, part production in switzerland.
I think at the price range we are talking here you should get a decent quality with each brand. Chose what you like.
At Bauwerk there are 3 categories how many branches you will finde. I think, ruhig, lebhaft and wild. In doubt I would always go with one category calmer.
We went thru a main contractor based out of Sierentz, France and they in turn brought in their Basel based sub-contractors. Coordinating everyone was a hassle but saved us a ton of money. If you want the contact details, I can send you via pm.
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