Boiler replacement, when to do it, and why a heat pump is the best replacement
Content:
- Boiler Replacement: When should you do it?
- Efficiency, why it is important.
- Government regulation and heat pump grants.
- Boilers vs Heat pumps
KNOWLEDGE HUB ARTICLE | Boilers vs Heat Pumps
1. Boiler Replacement: When should you do it?
Boiler replacement should happen when your boiler is older than 15 years old.
Start considering a boiler replacement when your boiler is older than 10 years old
Due to limited government grants on heat pumps and related technologies now can be the best time.
Constant or serious repairs indicate you need a new unit.
Older boilers can mean no warranty or discontinued parts.
If repair costs are particularly high, consider a new unit.
Boilers are one of the most intensively used household appliances. But faults can go unnoticed and then suddenly the heating will suddenly stop working.
A boiler breakdown can be costly, and especially in the middle of winter very inconvenient. But certain failures can also be a danger to you and your family if not spotted in time.
Most modern boilers can reach their maximum temperature quickly, so tepid or slow heating radiators could mean that your boiler needs replacing.
But it could also mean that your radiators need bleeding, or the central heating system is filled with sludge. These can cause blockages and cold spots on your radiators. Dirty water in the water system will result in long-term problems with your boiler.
All this results in your heating bills being as high as if your boiler is on full blast, but with a cold home.
Therefore if your home takes too long to heat up or your water doesn’t come through as hot as it used to, it might be time for a boiler service or a full replacement.
Carbon monoxide can be extremely dangerous and potentially fatal to you and your family. Although carbon monoxide itself is odourless, a smell could be created because the leak is causing the boiler to not burn properly. Any faint smells could indicate a carbon monoxide leak.
Other carbon monoxide warning signs that shouldn’t be ignored include:
- The boiler is burning a yellow flame instead of a crisp blue flame
- Dark soot stains on and around the appliance
- Pilot light that frequently blows out
- Increased condensation inside windows.
Symptoms of carbon monoxide poisoning include headaches, shortness of breath, nausea and unconsciousness.
If you notice any of these warning signs, you should evacuate your home straight away and call 0800 111999 (the emergency gas line) to get the leak inspected.
You and anyone else who have been in the property should be checked by a doctor. If you have a pet, take it to the vet, too.
The best way to ensure any carbon monoxide is detected as soon as possible is by installing a CO alarm in your home. You should have one – and if you live in Scotland you will be legally obliged to have one from February 2022 onwards.
As a heating system gets older, it can lose its efficiency and start to cost more to run.
You can use our simulation questionnaire to see what your energy bills might look like with a heat pump.
A leak can lead to further problems, such as rust and corrosion, as well as structural damage to your home. It will also mean that your heating will be inefficient through the wasted water.
Your boiler will make a noise when firing up, but this should be no more than a low and constant hum. Any noise outside of this should be a concern.
If your boiler is making funny noises you should turn it off immediately.
2. Efficiency, why it is important
The 2021 Heat and Buildings Strategy from the Department of Business, Energy and Industrial Strategy reported 77.1 megatonnes of greenhouse gas emissions from UK homes – that’s around 2,666kg per home, on average. In total, heating our homes accounts for around 17% of UK carbon emissions.
The UK is heading towards net zero carbon emissions by 2050. To achieve this, emissions will need to be reduced by 95%, to just 138kg a year per household by 2050 (Energy Savings Trust, 2021).
Since 2018, the government’s Boiler Plus legislation has required that all newly installed boilers have a minimum ErP efficiency of 92%, plus time and temperature controls fitted.
But a boiler’s efficiency depends on how it’s working in your home. A boiler won’t achieve its efficiency potential without compensation controls that adjust its flow temperature automatically.
As a general rule, a reasonably new boiler will have an efficiency of 90%. A 5 year old boiler 85%, and a 10 year old boiler 80%.
We have replaced boilers that are running at 72% efficiency.
The COP, or Coefficient Of Performance, indicates the efficiency of a heat pump or other appliance. The higher the COP value, the higher the efficiency and the more economical the appliance is.
The formula for determining COP is simple:
energy supplied / energy consumed = COP value
The SCOP value stands for Seasonal Coefficient of Performance and is the average COP viewed over a year, taking into account the different seasons. So this looks specifically at your region, averaging the COP values in your area over an entire year.
Our SCOP values are based on western European weather, and tested to this standard. The SCOP then indicates what the COP is when producing, say, 30°C water, 35°C, 40°C, 45°C, etc so you can easily compare whether the heat pump you have your eye on is above or below average.
The average COP value of Adlår’s heat pumps should be between 4 and 6. So this means that when you use 1 kW of energy you get 4 to 6 kW of heat in return. This is an efficiency of 400% to 600%!
We use the analogy of the tortoise and the hare to visualise boilers vs heat pumps when it comes to heating.
A gas boiler works fast, with high energy output to heat up water, whereas a heat pump works slow and steady holding the temperature at a more consistent level.
We also like to claim, as the tortoise, the heat pump wins the race.
Boiler Capacity
Traditional boilers tend to be oversized compared to heat pumps in terms of capacity.
As a general rule a house that requires 5kW of energy would tend to have a 30kW boiler installed.
This is because combi boilers are designed to be reactive, providing heating on demand. In this case, your thermostat will monitor your room temperature and turn the system ON and OFF to meet the desired room temperature. This creates a yo-yo affect between desired temperature and actual, and also between your inflow water temperature and your design flow temperature of your system (~35°C for underfloor heating and 45~80°C for radiators).
This greater temperature rise in this scenario requires more power.
Heat Pump Capacity
Heat pumps heat your water much more gently, over a longer period of time, and keep a constant flow.
Having heat pumps with a 30kW capacity requires an expensive unit, and usually 3-phase power to achieve. As a result, heat pumps are designed more carefully to facilitate lower capacity.
Heat pumps keep water flowing and by maintaining constant temperature in the system, there is rarely a need for a large surge in power to combat dropping room temperatures. The heat pump works to keep the water inflow temperature within a couple of degrees of your design flow temperature, rather than 5~10 degrees, as can be the case in a boiler system.
Heat Pump Extra Capacity
Adlår heat pumps are installed with extra capacity built in, and in combination with temperature sensors and pre-programmed environmental heating curves, we can account for the worst case scenarios (when outside temperature drops below -10°C, and the hot water temperature isn’t keeping up with your thermostat demanded temperature).
Our extra capacity includes:
- 3kW Immersion heater, within a 60 or 90 litre buffer tank
- 1.5kW domestic hot water (DHW) cylinder air source heat pump (ASHP)
The buffer tank smooths out demand, having heating hot water available to distribute to your heating system. The 3kW immersion heater can be activated if the heat pump’s capacity is close to maximum and the temperature settings aren’t being met by the heat pump alone.
The 1.5kW DHW ASHP cylinder works independently from the heating, to supply only for your domestic hot water. As DHW takes priority over room heating in most systems, by splitting the system as we do, we avoid the heat pump being in over capacity and prevents heating capacity for hot water from ever being diverted to the DHW.
This efficiency difference results is a significant impact to the environmental impact between heat pumps and boilers.
The CO₂ to produce 1kwh of heating energy:
- New Gas Boiler: 0.21 CO₂/kwh
- Old Gas Boiler: 0.23 CO₂/kwh
- Oil Boiler: 0.31 CO₂/kwh
- AURORA II: 0.11 CO₂/kwh
As an example:
- A 120m² house, with EPC of D could save 3,104 kg CO₂ a year with an AURORA II heat pump compared to their existing gas boiler.
- 4,600 kg CO₂ a year is the average UK per capita emissions per year (World Bank UK Data)
- This house example had 2 people living in it
- Their new household CO₂ a year is estimated at 3,048 kg.
- This equals 34% less CO₂ per person per year
3. Government regulation and heat pump grants
In order to reach the UK’s net zero target by 2050 the government are incentivising heat pumps to encourage people to make the change from boilers. The most accessible grant is the £5,000 boiler upgrade scheme.
The government have introduced a new bill which will require all rental properties to achieve an EPC rating of C or above by 2025.
https://bills.parliament.uk/bills/3036The Secretary of State must amend the Energy Efficiency (Private Rented 15 Property) (England and Wales) Regulations 2015 (SI 2015/962) to require that, subject to subsection (2)—
(a) all new tenancies must have an energy efficiency performance of at least EPC Band C from 31 December 2025; and
(b) all existing tenancies must be at least EPC Band C from 31 December 20 2028 where practical, cost-effective and affordable as defined under section 1(4).
In 2021, the government released its Heat and Buildings Strategy, which outlines the changes that will come into place over the next few years to make UK buildings more environmentally friendly.
This bill has not been passed yet, so it is not 100% confirmed whether the following phases will take effect at the proposed times or not.
Phase one: 2025
From 2025, gas boilers will be banned from all new builds.
Phase two: 2035
In addition to the 2025 goal, the Heat and Buildings Strategy also states that it’s aiming to phase out the installation of natural gas boilers beyond 2035.
This means that if your boiler goes kaput after 2035, you’ll need to install a low-carbon alternative, rather than a new gas or oil boiler.
Why is the government banning gas boilers?
As countries around the world continue to pump emissions into the atmosphere, climate change is getting worse. That’s why the UK has set out to be net zero by 2050 – and banning gas boilers is just the first of several steps designed to help reach this goal.
According to the Climate Change Committee, around 14% of UK greenhouse gas emissions come from domestic energy use – mostly from our gas boilers keeping us toasty. But if we want our country to be net zero by 2050, we need to drastically reduce this figure.
Knowledge Hub | Boiler Upgrade Scheme
The Boiler Upgrade Scheme (BUS) supports the decarbonisation of heat in buildings. It provides upfront capital grants to support the installation of heat pumps and biomass boilers in homes and non-domestic buildings in England and Wales.
Availability: England and Wales
Funding Available: £5,000 towards the cost and installation of an air source heat pump
There are a number of local heat pump grants available from local councils. Adlår tries to stay on top of these grants and share them with our customers, but we also recommend you contact your local council and see what extra funding is available.
Local governments have targets to achieve on emissions and are making money available for this purpose.
See below for an example from Hampshire.
An example of one of these grants is: The Energy Saving Trust (EST) Redress Grant:
Availability: Householders living in the Winchester and Petersfield area in Hampshire
Funding available: No single homeowner will be eligible for more than £7,500 for grant funding support.
- Heat pump essential enabling works e.g. radiator upgrades, rewires approved on a case by case basis – £1,000 or max 50% of the cost of the work
4. Boilers vs Heat Pumps
There are a number of key differences between a boiler and a heat pump. Here we list some of key differences.
- Energy consumption
- Energy Costs
- EPC Upgrade
- Environmental Impact
- ROI/Payback
- Cooling ability
- Your Property Value
- Way of heating
- Other considerations
The Better Homes, Cooler Planet report also estimated that by installing a heat pump in your home you could reduce your heating costs by around 37%. or £1,290.90 on average.
Heat Pump Costs | Savings, Payback, Investment
The payback period and return on your heat pump investment depends on which heat pump you have, the gas consumption you would have if you didn’t have a heat pump and the energy costs. Once you have all this mapped out, you can do a calculation on this. Adlår’s quick savings questionnaire can give you a good idea of your homes specific situation.
The Regulatory Assistance Project (RAP) suggests that if designed and installed well a heat pump can be cheaper than a gas boiler by up to 27%.
Using a rough demostration from People Powered Retrofit’s home assessment tool, it’s possible to see the potential of a low, medium and high impact retrofit, and the size of heat pump that could then be used i.e. small, medium and large.
- Baseline scenario: Peak heat load = 11.1kW (large heat pump required)
- Scenario 1 low impact retrofit: Peak heat load = 8.8kW (medium heat pump)
- Scenario 2 medium impact retrofit: Peak heat load = 5.1kW (small heat pump)
- Scenario 3 high impact retrofit: Peak heat load = 3.8kW (small heat pump)
What can be seen here is that any kind of retrofit reduces the size of the heat pump required – but a deep retrofit has a significant impact.
It is difficult to say exactly how much you can save, if anything, without looking at your specific home setup. In order to get an initial understanding we encourage you to fill out our questionnaire to get an initial market leading simulation.
Heat Pump Quote and Performance Simulation
How much does a heat pump add value to my home?
A WWF report, in conjunction with Scottish Power (Better Homes, Cooler Planet) has shown a heat pump could add between 1.7% and 3.0% to the value of your home, or £5,015 (1.7%) to £8,850 (3.0%) based on the Office of National Statistics UK average house price of £295,000 in November 2022.
The Better Homes, Cooler Planet report also estimated that by installing a heat pump in your home you could reduce your heating costs by around 37%. or £1,290.90 on average.
The report also highlighted a heat pump outperforming other forms of renewables, such as electric vehicle charging or solar panels.
…
According to Knight Frank’s Property Market Insights, improving your EPC rating can improve your home value by a further 20%.
…
Additionally, as Adlår’s heat pumps can facilitate cooling, your property value could increase by as much as 2.5%.
The heating of our homes accounts for 14% of the UK’s total carbon emissions. New energy methods, such as heat pumps, can make a significant difference to lowering this.
The CO₂ to produce 1kwh of heating energy:
- New Gas Boiler: 0.21 CO₂/kwh
- Old Gas Boiler: 0.23 CO₂/kwh
- Oil Boiler: 0.31 CO₂/kwh
- AURORA II: 0.11 CO₂/kwh
As an example:
- A 120m² house, with EPC of D could save 3,104 kg CO₂ a year with an AURORA II heat pump compared to their existing gas boiler.
- 4,600 kg CO₂ a year is the average UK per capita emissions per year (World Bank UK Data)
- This house example had 2 people living in it
- Their new household CO₂ a year is estimated at 3,048 kg.
- This equals 34% less CO₂ per person per year
The calculations behind the EPC rating are not based purely on efficiency, they’re based on the cost of heating and powering your home. That means the cheaper the running costs, the better the rating.
It is therefore important to get a detailed survey done of your property. The best start is to complete our market leading initial assessment to understand your savings.
…
Using an example of a property we installed a heat pump on. The comparable data shows you how a heat pump can be the best solution to improve your EPC.
…
AURORA II 10kW HEAT PUMP
- Price: £5,853
- Yearly saving: £671*
- EPC Increase: 8**
Comparison:
- Heat Pump: £731.63 Cost/EPC
- Wall Insulation: £1,250 Cost/EPC
- Solar Panels: £785.71 Cost/EPC
As can be seen here the heat pump is the most cost effective solution in this case. It is important that this varies property to property and we encourage you to complete our survey for accurate results for your home’s specific circumstances.
As Adlår’s heat pumps can facilitate cooling, your property value could increase by as much as 2.5%.
ASHPs provide both heating and cooling technology so they can be a versatile solution for year-round comfort. They can reverse their operation, extracting heat from the home and expelling it outside during the summer, therefore acting as a sort of air conditioner. The heat pump works by absorbing heat from the outside environment during the heating phase, and in the cool phase reserves the process, absorbing heat from your home and sending it back out into the outside air.
Are Air Source Heat Pumps Really That Noisy?
One of the main concerns about heat pump disadvantages is that they are noisy. This just isn’t the case with modern units. There are now strict regulations on how loud this can be (around 40 – 60 decibels within one metre). Our heat pump is only 42bd from 1m.
That’s roughly the same as a fridge freezer or a gas boiler and because they’re outside, the noise will rarely be heard. Our site survey includes a noise check to ensure this.
Read more in our Knowledge Hub page on this topic.
Before installation we do a thorough home survey to ensure the heat pump system we install is optimised for your space.
Unlike a gas boiler, where high bursts of energy are produced, rapidly heating, a heat pump is designed to stay on for longer without costing you more – keeping consistent temperature throughout the day. The rapid inefficient burst of burnt energy with a boiler verses the slow consistent operation of a heat pump is one of the core reasons for the massive difference in heat pump efficiency and cost savings.
Air source heat pumps can actually work in temperatures as low as -20 °C when properly installed. Norway, Sweden, and Finland have the highest heat pump adoption rates in Europe, and are equally some of the coldest countries.
When it gets very cold, the heat pump will need to use a bit more energy than usual to keep your home cosy, but as our heat pump is designed for Swedish winters, the UK’s milder climate means our heat pump has no problem keeping up.
Our heat pumps are also installed with outdoor temperature sensors and climate control systems, which can engage immersion heaters to boost hot water if in the rare case the heat pump isn’t efficiently getting your hot water up to the design flow temperature.
With the Government’s Boiler Upgrade Scheme £5,000 grant, you can get an ROI on your investment and saving on your gas bill quickly. We give you a detailed overview of your savings, and comparison to new and older gas boilers when you complete our online questionnaire.
A heat pump can last 20 years – about twice as long as a boiler – and they need less pricey maintenance.
Our installations include a 2, 5 or 7 year warranty depending on your service packages.
Read about our industry leading maintenance packages here.
These days heat pumps can actually heat water up to these higher temperatures.
The question is, why would you want to? Heat pumps work more efficiently at lower temperatures and with modern low temperature radiators you just don’t need to heat your water up to 60 degrees, or higher.
By running your radiators slightly longer at a lower temperature you save money, have less heat loss in your radiators, and have a more pleasant living environment.
Heat pumps are smart. They use outside temperatures to control your heating curves and with your input they can learn your usage and active times in the house to ensure that slow and steady heat is produced so when you walk in your home the temperature is perfect.
Then it works slow and steady in low eco modes to maintain that temperature.
You don’t need to worry about going to the thermostat and hitting boost.
The outside main unit is roughly 1m x 1m x 1.5m, it needs a space of ~1m meter infront and to each side to allow optimal airflow into the unit.
Inside you need space for a hot water cylinder, which is roughly 2m x 1m x1m (the size of a small-medium sized modern fridge), which you can place on the ground or first floor of your home (the closer to the outside the better).
Heat pumps can work in nearly all homes, our 14kW unit is powerful enough for a 200m² home. We can install multiple units, but we need to do a proper onsite survey to establish if this is feasible and affordable.
We pride ourselves on our initial questionnaire being more detailed then other providers, so you can immediately receive a solid understanding of your heat loss, costs and savings.
Adlår Castra
Our mission is to accelerate the transition to renewable energy by making it affordable for households in Western Europe. We understand that the transition to renewable energy is crucial for the future of our planet and we believe that everyone should have access to affordable and sustainable energy solutions.
That is why we offer a range of high-quality and cost-effective heat pumps designed to help households reduce their CO2 emissions and save money on their energy bills. We are committed to providing our customers with the best possible service and support, and we are determined to help them make the switch to renewable energy as easy and seamless as possible.
Top Articles
LINKS
- Knowledge Hub
- Knowledge Hub Directory
- Performance Simulation
- Free Advice
- Free Brochure
- About Adlar
