Rishi Sunak’s swimming pool – analysing the pool heating bill

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Last updated – 15 June 2023 (15 minute read)

How much did the Energy Price Guarantee save Rishi Sunak on his swimming pool heating bill?

With the Energy Price Cap falling below the Energy Price Guarantee (EPG) from 1 July 2023, the EPG is about to fall away and, at least for the time being, to become redundant. However, before we leave the subject, we thought it might be worth looking at one specific potential beneficiary of the EPG.

One of the benefits of the Energy Price Guarantee is that it is a universal scheme. Everyone receives it irrespective of their financial standing. This however, is also one of the criticisms of the scheme. Critics and charities have argued that it was not targeted enough. Bu definition, it isn’t. Ironically though, this didn’t stop those very same charities pushing for an extension to the EPG. Cos, you know, Martin Lewis said so. Anyway, we digress.

Being a universal benefit means that it is subsidising heating bills for swimming pools of the rich, the very rich, the uber rich, and the famous. We couldn’t help noticing that, just around the time that the EPG was being introduced, our very own Rishi Sunak was building his very own private swimming pool on his very own private Yorkshire estate.

We couldn’t help wondering. Did the heating bill for Rishi Sunak’s new private swimming pool benefit from the EPG subsidy? And, if so, by how much? We decided to take a closer look.

Just to be clear. We have no idea whether Rishi Sunak got any meaningful subsidies from the EPG. We are definitely not making any assertions that he did. He will have received some kickbacks from the Energy Price Guarantee; we all did. We are merely presenting some scenarios around the build and heating to his new swimming pool, to gauge the level of subsidy he might have received, if he received it. That’s all.

Calculating the cost of heating Rishi Sunak’s private swimming pool?

Here will focus on the initial heating bill only, rather than the ongoing heating bills. We have also ignored energy losses in the initial estimate. Therefore, our estimates will be, we believe, on the low side.

To calculate how much Rishi Sunak might have benefitted from the EPG, we first need to calculate the amount of energy required to heat his new swimming pool. To do this we need to find out, or estimate, the following.

1. The size and shape of the swimming pool. This will determine the volume of water that it holds.

2. The final desired temperature of the water in the pool.

3. The temperature of the water initially used to fill the pool.

From 2 and 3 we can calculate the energy required to heat the water in the pool to the desired temperature.

Once we have estimated the energy required to heat the pool, we can apply the EPG discount to each kWh to calculate how much of a kick back, if any, Rishi Sunak might have received.

We are not swimming pool design or heating experts. So this is not designed to be a detailed energy assessment or any such like. Although, in researching this article, we did learn more about swimming pool design that we ever expected to. Fascinating stuff. However, we do know enough of the basics of the maths and physics involved, and a thing or two about energy prices, to be able to provide a ballpark analysis.

How big is Rishi Sunak’s swimming pool?

The swimming pool that we are referring to is the relatively newly built one at his North Yorkshire manor house. Rishi Sunak may own other properties with swimming pools, but these are not considered here.

On 18 May 2021, consultants on behalf of Rishi Sunak filed a planning application “for the formation of a detached ancillary building”, which “would include a utility and changing area, plant room and a swimming pool. Directly east of this a private domestic tennis court is also proposed.” The planning application was approved (with conditions) on 28 August 2021.

From the planning application, we know that the swimming pool is rectangular, measuring 12m x 5m.

Details of the depth of the pool are not provided, so we have to estimate this. The only other feature in the application drawings, is a set of classic round corner steps built into one of the corners of the pool. We don’t know whether this design was followed exactly, but we will assume that it was.

Details of the size and shape of Rishi Sunak’s swimming pool can be verified online from the application planning documents. As these come with a private address, to respect Rishi Sunak’s family’s privacy (and to ensure we don’t fall foul of any privacy rules we may not be aware of), we are not going to provide direct links here. However, a small amount of investigative Googling can easily uncover the information for those interested.

In summary, this is a simplified aerial view plan of Rishi Sunak’s new swimming pool.

Plan view of Rishi Sunak's new private swimming pool at his Yorkshire estate - energyscanner

How much water does Rishi Sunak’s private swimming pool hold?

We don’t know the depth of Rishi Sunak’s swimming pool, so we will have to make an educated guess.

Since Rishi Sunak has a relatively young family, it seems reasonable to assume that he built a family friendly pool. That is, something big enough and deep enough for playing, diving and jumping as well as for swimming lengths. It seems likely therefore that the pool would have a shallow section of a few meters, and then slope to a deeper section.

This is pure guesswork on our part, but we’ve gone for the following dimensions.

(Assumed) cross-section view of Rishi Sunak's new private swimming pool at his Yorkshire estate - energyscanner

We are almost certainly wrong about this but hopefully not by an order of magnitude or anything crazy like that. Risk wise, the pool could theoretically be much deeper, than it could be much shallower. 

The pool likely holds over 100,000 litres of water

The total gross volume of the pool is made up of…(in each case taking length x width x height);

The shallow part = 3.5m x 5m x 1.2m = 21m3

The sloping part = 2m x 5m x ½ (1.2 + 2)m = 16m3

The deep part = 6.5m x 5m x 2m = 65m3

Giving a total gross volume of 102m3

From this we need to deduct the volume of the steps.

The steps really aren’t going to make a huge difference given the margin of error involved in the guesswork above. However, for completeness, let’s do the calculation.

The pool plan shows the step design to be classic, round corner, quadrant shaped steps. A shallow end of 1.2m would require 4 submerged steps each of 0.24m depth, with the final step being onto dry land. We will take the radius of the submerged quadrants to be 0.4m, 0.7m, 1.0m and 1.3m respectively.

The volume of each step is given by the area of the quadrant times its height, which is

(∏r2)/4 * h

Collecting common terms, we get

(∏h)/4 * (r12 + r22 + r32 + r42)

Substituting in values gives

(0.24∏)/4 * [(0.4)2 + (0.7)2 + (1.0)2 + (1.3)2] = 0.63 m3.

Deducting this from the gross volume gives 101.37 m3. We will round to 101 m3 to avoid spurious accuracy. That’s 101,000 litres, which is a lot of bathtubs full.

By how much does the water in Rishi Sunak’s swimming pool need to be heated?

That is arguably the biggest unknown in this calculation.

The amount of energy required to heat a swimming pool is a function of 3 things.

  1. The volume of water (which we have estimated above).
  2. The temperature differential between the input source (the mains) and the desired operating temperature of the pool.
  3. The efficiency of the heating system used to heat the water.

One of the significant properties of water, which makes it such a stable environment for life on earth, is that it takes a lot of energy to heat it. Water has to absorb precisely 4,184 Joules of heat (1 kilocalorie) for the temperature of one kilogram of water to increase 1°C.

One litre of water has a mass of almost exactly one kilogram when measured at its maximal density, which occurs at about 4 °C. This will vary slightly as temperature increases, but by such small amounts that don’t matter for the purposes of our calculation.

We have estimated that the pool holds around 101,000 litres of water. This is equal to 101,000 kg

1 Joule is equal to 0.0000002778 kilowatt hours. Inverting this gives, 1 kWh = 3.6 MJ (million joules).

To heat Rishi’s swimming pool by 1°C would require (4,184 * 101,000) / 3,599,712 = 117.4 kWh of energy.

According to the Danthern Group, a European company with a long history in portable and installed climate control solutions, private swimming pools are typically heated to 26°C-30°C. Who are we to argue? Let’s take the centre of that range and assume that the Sunak’s are happy with a relatively pleasant 28°C heated pool.

What was the temperature of the water used to fill the pool?

There is no question that the water to fill the pool originally came from the mains. They may be wealthy, but surely the Sunaks would not have used bottled water…. would they?

According to data from Severn Trent published on the WhatdoTheyKnow website, average mains water temperatures follow a seasonal pattern and range from lows of 6°C in the winter through to 18°C in the summer.

On this basis, heating the water from mains tap temperature, through to the desired 28°C , would have required a minimum of 10 * 117.4 kWh = 1,174 kWh of energy, through to a maximum of 22 * 117.4 kWh = 2,583 kWh of energy.

We will make one further assumption. That the new pool build came with a new, efficient, state of the art heating system with an energy efficiency of 85% (energy out to energy in ratio). Factoring in this energy loss, means that the energy required increases from a minimum of 1,381 kWh to a maximum of 3,038 kWh.

There is, however, another possibility. What if the swimming pool was filled during the summer months? Remember the 40°C heatwave in July 2022? For new builds such as this one, some pool companies follow a construction plan where the pool is built, filled with water and covered first, and then the new building housing it is built around it. Building it this way, means that the water in the pool heats to background ambient temperatures naturally during the course of build. This reduces the amount of external heating required to attain the desired temperature. In the optimal case, minimal external heating may have been required. Worth noting though that a couple of 40°C days isn’t going to make much of a dent in a 101,000 litre pool of cold water.

When was Rishi Sunak’s private swimming pool completed?

Why does this matter? Indeed, is this even the right question?

Depending upon when the water in the pool was first heated, will determine;

(a) how much energy was required to heat the water to the desired temperature,

(b) whether the heating bill qualified for a subsidy under the Energy Price Guarantee and

(c) how much that subsidy was likely to be.

Clearly, we do not know the answer to these questions. So the best that we can do to present some scenarios. Firstly, let’s see what we know, or can infer from, previously published information.

Arial photos, from various online sources show that construction was well under way by August 2022. This arial shot from the Daily Mail, dated 12 August 2022, shows the new building largely complete suggesting that the pool was likely already finished and possibly also filled.

On 12 Mar 2023, the Guardian reported that Construction work on Sunak’s private 12-metre (40ft) swimming pool has finished”. It also reported that “Rishi Sunak’s new private heated swimming pool uses so much energy that the local electricity network had to be upgraded to meet its power demands,…”.

We envisage 3 possible scenarios.

Scenario 1

The pool was filled with water before the building around it went up. In this scenario, the swimming pool and was brought up to its operating temperature before the Energy Price Guarantee came into effect.

Scenario 2

The pool was filled and heated during the Oct-Dec 2022 quarter when the Energy Price Guarantee kicked in. In this scenario, Rishi Sunak would have received the EPG subsidy on his pool energy bills.

Scenario 3

The pool was filled and heated during the Jan-Mar 2023 quarter. This would have required the maximum amount of energy due to temperature differentials. It would also have qualified for the biggest EPG subsidy due to large price differentials between the Energy Price Guarantee and the Energy Price Cap at that time.

How the Energy Price Guarantee subsidises the heating costs of private swimming pools

The Energy Price Guarantee works by putting a limit on the unit rates for gas and electricity that energy suppliers can charge. That limit is determined with reference to a target annual energy bill for a household with average energy usage. The target bill is £2,500 a year.

Rather than just make up any random combination of gas / electricity price pairs to achieve this goal, the EPG does this by discounting each unit of gas and electricity by a given amount relative to an existing benchmark, the Energy Price Cap. The Energy Price Cap is (supposed to be) calculated with reference to the actual market-based costs that energy suppliers face. Given this, the approach has the benefit of keeping market-based pricing within the subsidised EPG price (as opposed to creating another wild pricing distortion). But the main reason why the Energy Price Cap benchmark was used is because it was already there. And that it the quickest and most convenient way of getting the Energy Price Guarantee implemented.

The level of the EPG subsidy varies by quarter and is the difference between the Energy Price Cap (which varies quarterly with market-based prices) and the desired level of the Energy Price Guarantee (which is determined by government based upon what they can afford / get away with / get bullied into providing etc. *) (* delete as appropriate).

How much of Rishi Sunak’s private swimming pool heating bill was covered by the taxpayer?

Here we only need to consider Scenarios 2 and 3. In scenario 1 above, there is no initial subsidy, so there is nothing to calculate.

The per unit subsidies for the periods in question are shown in the Table below together with our heating cost calculations. Only the electricity unit discounts are shown. This is because the Yorkshire village where the Sunaks live is not connected to the mains gas grid. This means that their swimming pool would need to have been heated using either an electric boiler, or using alternative fuels such as oil or LPG. We have assumed the pool is heated with an electric boiler. The fact that the local electricity network had to be upgraded to meet the power demands of the new pool, as reported by the Guardian, would tend to support this.

Period Oct-Dec 2022Jan-Mar 2023
Unit rates (Yorkshire) (incl VAT)
Electricity price (EPG)p / kWh33.03
Electricity subsidyp / kWh17.85 31.8
Temperature differentials
Input temperature°C117
Output temperature°C2828
Temperature differential°C1721
Energy consumedkWh1,9962,465
After efficiency losses (85%)kWh2,3482,900
Energy Costs (units only)£776957
EPG Subsidy£419922
Total Cost to heat pool£1,1951,879
Source; energyscanner

It depends…

If Rishi Sunak heated his new swimming pool in Q4 2022, then we estimate that it would have cost him around £780 on a one-off basis. On top of this, his energy bill would have been subsidised to the tune of £420 by the EPG; paid for by the taxpayer.

However, if Rishi Sunak heated his new swimming pool in the winter during Q1 2023, then the cost would have risen to around £960. This would have been subsidised to the tune of £920 by the Energy price Guarantee.

Of course, there is the possibility that the swimming pool was heated much more efficiently during the summer of 2022 when background ambient temperatures did most of the heavy lifting. In this case, taxpayers would not have needed to subsidise any of the initial pool heating bill. However, with large private swimming pools there are always ongoing maintenance charges and heating bills. These costs have not been considered here. However, the Sunaks would definitely have benefitted from those subsidies during the Energy Price Guarantee period. And, until 30 June 2023, they will continue to do so.


Overall, if Rishi Sunak benefitted from the Energy Price Guarantee subsidy, then that benefit would have been large but not outrageous. In fact, what surprises us about this analysis, is that large private pools can be heated for less than we expected. There have been reports suggesting that the annual cost of heating the pool would be £13,000 a year. Our numbers suggest it should be a lot less than this. Sure, a one-off heat-up can cost the same as the electricity bill of the average household for a whole year. However, for a family whose net worth is nudging the £1 billion mark, that is a drop in a very large ocean.

We hope you enjoyed this article. If you spot any errors, know more about the timing of the pool build, or have any other, non-spam comments, please drop us a line below.

Read more

– Energy Price Cap Guide

What is the Energy Price Guarantee

Companies making cost of living payments

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