Getting a heat pump is a daunting task. There seems to be a ridiculous amount to learn if you want to understand every nut and bolt of what you're spending your hard earned money on.
Due to the vast difference in quality of heat pump installer, all of this learning is probably absolutely necessary.
In reality though, once you have found a decent heat pump installer, you should be able to trust them to crack-on under your guidance, which will make the whole installation a lot smoother.
The two main types of companies you'll find are sales based companies (which employ salesmen) and engineer based companies which are typically smaller, led by what works and look for how to get the most efficiency.
Our task here is to give you a list of questions or points that will both test your heat pump installer and simultaneously teach you about what to look for.
Luckily, most of the former types of companies send salesmen out rather than engineers so they're very easy to spot.
The first question will give a very big clue: Ask the guy who's out looking at your system or giving a preliminary quote over the phone, how long they have been a heating engineer for or what their background is?
If the answer is that they aren't a heating engineer and describe their role as more sales based, and perhaps were previously in another industry, it's a clue that they aren't really system specifiers (which is a complex job).
It may indicate that they can’t really accurately quote your job for the best efficiency or look for any quick wins with efficiency on your property.
As part of this I would also ask how long the company has been around for.
They don't necessarily have to be on the MCS register, but companies that have been around for longer will have generally been around longer for a reason and they have a lot more to lose.
The vast majority of cowboy companies don't tend to last long in the heat pump industry as they lack the attention to detail that is required to be successful.
I would actually suggest potentially keeping this question quiet, and up your sleeve until later on.
The single biggest thing that affects system efficiency is the system design temperature.
That basically means what the heating system's water temperature needs to be when it's around -2°C or -3°C outside.
It's very easy to design a system to work at higher temperatures to provide you with a nice cheap quote or make more money due to having to replace less radiators.
But it's your prerogative to potentially spend more on a system that uses less electricity, not theirs.
If they’re willing to provide you with a quote without having this important discussion about designing for lower flow temperatures, then they could just be trying to do it as cheaply as possible.
If you have underfloor heating everywhere and no radiators, or your system is naturally going to be low temperature because it is very, very well insulated (say 35°C) off the bat, then this may not be mentioned much at all.
Another way of tackling this subject is to look at or ask what SCOP (or efficiency) they are designing to.
A system which has been designed to a SCOP of 3 is not the same value as a system designed to a SCOP of 5.
Quick note: SCOP is your seasonal coefficient. A SCOP of 3 means 1 unit of electricity gives 3 units of heat. SCOP of 5 means 1 unit of electricity for 5 units heat.
Once you get the quote, bring this up with your specifier and see how they respond. It might give you a few clues.
Ok, the next clue is that they offer hybrid systems over new rads, or dont use a hybrid as a last resort, or high temperature heat pumps.
A good engineer will always be looking to go fully heat pump first.
So what I mean by a hybrid system is a system that uses a boiler and heat pump.
This can be added to your current system or offered as extra and will turn on the boiler when it gets colder.
It's sometimes used as a lazy way of selling mass units and means no real design or consultation is needed.
If you have a particularly large property, or very low levels of insulation that cannot be improved, a hybrid may be the only solution.
But in reality if it's below 250sqm and post war and reasonable insulation, you're very unlikely to need a hybrid.
A good engineer will take you through a whole consultation process, this may even be charged for and come off the installation once you have selected that contractor.
During this process the engineer will advise how much you will need to upgrade your radiators or increase your insulation by, in order to install a non-hybrid system.
As I say, there are some cases with larger listed properties where you may not want to spend too much time looking at other options. But the conversation should still be touched on to confirm its viability.
If they're offering a hybrid for a normal house straight away before calculations, flow temperature discussions or radiator size discussions, then you will likely end up paying more and they will make more, leaving you without a grant or a lesser grant.
Another pointer, if they are pointing to a ‘high temperature unit’ that's often the same indicator.
Engineers usually look at how to get the temperature down if needed. Just putting in a high temp unit minimises risk of poor installs, but also lowers your potential system efficiency.
Next is over sized units. Have they quoted you for a 16 kw unit?
The boiler industry has left a huge legacy of over-sized heat sources. Rules of thumb haven't been updated and combination boilers left the mythical thinking of bigger being better.
This is not correct for boilers or heat pumps but boilers being so forgiving don't really display the issues it brings as obviously. In actual fact the average house is only 6-8kW.
That's 6-8kW whether you're heating with a heat pump, gas boiler or hamsters in wheels, the heat requirement is the heat requirement.
And the closer we match your heat source to the requirement, the more efficiency you'll have due to reduced cycling and lower possible flow temperatures, and this is especially important for heat pumps as this is crucial for higher SCOP.
As a general rule, I would actually say that the engineer with the lowest suggestion of heat load would be right as even the in depth calculations are over egged by 10% or so.
Through a few years of doing heat losses and using boiler and heat pump controls that actually display the real life heat output of an appliance at harsh winter conditions we can say this quite confidently.
Also remember that although engineers say they have completed heat loss calculations they very much vary on how in depth they are.
If your surveyor has not measured every window, wall and door, as well as looked at depth of loft insulation, enquired about cavity insulation and measured every radiator!
They have not done any heat loss calculations. Just the details of the heat loss survey alone should take 1 to 2 hours on site to obtain excluding the time spent talking to you about any options etc.
If you get to the installation stage and this information still hasn't been taken, stop the installation and abandon the contract.
If you are questioning the size of the unit required, you can use a service similar to what Veritherm offer .
They place sensors internally and outside, you leave the property for a night and they produce a report of actual real world heat loss.
To save you some time, and to give you an idea of what to expect. We've built you a custom cheat sheet to give you an idea of your real world heat loss. This will show you which companies are over specifying and who's not.
Check out our How to Size Your Heat Pump / Boiler video below.
Lastly, are they a Heat Geek? Can they prove competence in understanding hydraulic design?
As of time of video, there is only 1 low temperature low temperature heating design course and that's the Heat Geek Mastery course https://courses.heatgeek.com/.
There’s a 2 day course on the way, but the Heat Geek course would take 3 weeks or so to complete in a classroom.
Check out our map and you'll find local engineers that have had to go through an extremely Extensive and difficult course, which is not a simple pay to pass or A to D answer variation.
Which alone is a significant achievement which certifies their attention to detail and passion for the trade. Outside of this you would probably just have to take the engineers' word for it.
If you want an engineer who really knows his onions, please take a look at our Find a Heat Geek page where you will find engineers that have undertaken the best training in the business!
Enjoyed this article? Want to know more about system design and how to become a top heating engineer?