replace large outdoor unit with smaller one
I have a complex issue with the heat pump that was fitted to my house - far too big and unaffordable to run. There are many reasons for this but the main one is that I was not given a choice. The six heat pump installers who have visited since disengaging from the cashmachine that did the intitial work, have all tried to make decisions for me - they know best and they quote £7k, £4k and £1.2k, without showing any proof that they know what they are talking about. Most do not seem to have any credentials regarding the environment etc. and two out the six were intent of selling biofuels or lpg systems.
I am reasonably convinced that a heat pump is the right solution for my house, especially as there is one fitted! I cannot solve all its problems in one post so I have reduced my question to this:
If I disconnect the 16KW Samsung out door unit and replace it with a 5Kw unit, will the rest of the system accept the new device without needing an expensive installer?
I have many spreadsheets full of heat loss data, all diffferent, all dependent on the guess work of experts, none of which are trustworthy or beleaveable. I have 55sq mtrs of living space that I want to heat with ufh in most of the space that requires heat. I have followed discussionsand the MCS spreadsheet is an excuse to oversize the hp and laugh all the way to the bank.
This one makes sense and suggests that 5kw would be sufficient.
55m2 is a very small heated area, a 5kW unit would provide 90W/m2, which is at the higher end of the 65-85W/m2 'typical installed heating load' for a home, especially underfloor. You have spent a lot more time researching your requirements than any of the professionals you've engaged with, and you know best how you want to heat the property, what heating profile (24/7, timed, etc.) and what works for you.
I asked my MCS installer to drop from their calculated 13kW ASHP (Heat Engineer software) to my calculated 10kW. My calculations took in some diversity - we don't heat all the rooms in the house all the time to 22 or 23degC. This winter has validated my 10kW ASHP as 'right sized' not oversized. The practical difference meaning the ASHP can modulate down to 20% without cycling on and off on low load.
It coped, just, during the very cold two weeks before Christmas, but that was due to spending so much time in defrost, which all ASHPs are similarly afflicted with. I would sooner have the system a little slow to warm up and maybe struggle a little for 3-4 weeks a year than be oversized for the remaining 18-20 weeks of a typical UK heating season. I can always put the log burner on if I need to boost the downstairs quickly, and we prefer cooler bedrooms upstairs.
In my mind, oversizing plant is just as bad as under-sizing. Others on here have a view which may differ. It certainly costs more to run oversized heating plant, whether gas, oil, ASHP or whatever. It's inefficient too. In my day job I calculate, size and specify custom build HVAC equipment for projects that cost several millions of pounds to purchase, so maybe I'm a little more sensitive to adding contingencies and factors of ignorance onto equipment capacities than most. 😉
- 24 Forums
- 1,427 Topics
- 30 K Posts
- 13 Online
- 1,214 Members
Join Us!
Latest Posts
-
RE: Is this a bad installation and is there something wrong with my Samsung heat pump?
@kenbone no need for what kenbone regarding the 100watt...
By David999 , 10 hours ago
-
RE: Insulation of flow and return Heat Pump piping
@mike-h Thanks Mike. Toodles.
By Toodles , 13 hours ago
-
RE: Bivalent (or even trivalent!) system design options for a new GSHP installation
For your interest @algienon this is what happens when a...
By Transparent , 14 hours ago
-
RE: Rising Damp – Production Recommendation
Yet another topic I'm not an expert in. Nonetheless, th...
By Majordennisbloodnok , 18 hours ago
-
RE: Noise problems with newly installed Samsung 8kW ASHP
@editor yes, the more I read the forum posts the more I...
By sjn , 19 hours ago
-
RE: Observations on my Ecodan's estimates of energy consumed and delivered
As it is possible for the FTC to be powered from a sepa...
By HarriUp , 1 day ago
-
RE: ASHP Cut-off Temperatures: What's Your Setting and is a Your Heating Still On?
My system has been running 24/7 on weather compensation...
By HughF , 1 day ago
-
RE: Heat Pump Truth or Myth#2 - Cycling uses a lot of power and ruins your COP
I cannot state that I have noticed that our A2A heat pu...
By Derek M , 1 day ago
-
RE: Maximising Savings: Navigating My First Year with Octopus Energy and Heat Pump Running Costs
@toodles I can also happily report that the Agile tarif...
By Steve D , 1 day ago
-
@editor As we all know, RHH always strive to educate, e...
By Toodles , 2 days ago
-
@bontwoody I used the website link to contact them for ...
By Toodles , 2 days ago
-
RE: Samsung ASHP power cycling
I have considered that and I would have expected to see...
By Blaine_t , 2 days ago
-
RE: 14kW Midea ASHP in an old leaky building
Hi @batalto. I see you have a Midea ASHP and I am sched...
By Kbedders , 2 days ago
-
RE: Additional ASHP kW for DHW cylinder?
We're in a similar boat to you with a hodgepodge of dif...
By Mars , 2 days ago
-
RE: No-code, plug-and-play monitoring for your heat pump
Anyway, so far we have all missed the main protagonist ...
By Toodles , 2 days ago
-
RE: Are Octopuses Slowing Consumer Adoption of Heat Pumps?
@ivanopinion Im in the same team as Ivan. I think for a...
By bontwoody , 3 days ago
-
RE: Issues with Vaillant connectivity via the MyCONNECT gateway
@drew-pa I don't know about hard work! It is pretty cl...
By dr_dongle , 4 days ago
-
RE: Are Solar Diverters Necessary for Homes with ASHPs and Solar PV?
@editor No, I made one 😀 Loft insulation all...
By Andris , 4 days ago
-
@hughf Thanks for that. Ah so they are talking about ...
By IRMartini , 5 days ago
-
RE: Ecodan software update. Real or scam?
@abernyte, hmm, must have been a major disruption if 40...
By Mars , 5 days ago
Latest Topics
-
By Toodles 2 days ago
-
By Blaine_t 2 days ago
-
Insulation of flow and return Heat Pump piping
By Toodles 2 days ago
-
Rising Damp – Production Recommendation
By Mars 2 days ago
-
Additional ASHP kW for DHW cylinder?
By Project_Electrify 2 days ago
-
By IRMartini 5 days ago
-
Riello / Midea - modbus set flow temp
By stuartornum 5 days ago
-
Ecodan software update. Real or scam?
By Morgan 6 days ago
-
Noise problems with newly installed Samsung 8kW ASHP
By Lokisam 1 week ago