Low flow showers are said to save you money but is this true?
A domestic shower uses between 6 – 20 litres of water per minute at 40 oC. How much water used depends on the shower head, whether it is a low flow or high flow head (as well as the person using it – obviously). In energy terms the amount of energy used is between 0.2 kWh per minute and 0.7 kWh per minute.
The economics are quite interesting. The operating cost of low flow showers are around 3p for every minute, while high flow showers are 10p for every minute (not including the cost of water and the cost of effluent) this is based on electricity heating. The costs are 0.6p per minute for low flow and 2p per minute for high flow if using natural gas heating (a lot cheaper).
The average time a person spends in a shower on a daily basis is roughly 8 minutes (research suggest 7 minutes for a Gent and 9 minutes for a Lady). If the average person were to shower every day then the annual cost of simply showing will range from £87.60 to £292 per annum for electric and £17.52 to £58.40 for natural gas (LPG and Oil is somewhere in between).
Now we have 5 adults in our house that shower every day. We have high flow showers and we use natural gas for water heating. The annual cost in relation to people showing in our house is therefore around £292. The crazy thing about this is that this is equal to 25% of our energy costs for the year.
Low flow shower heads cost in the region of £25 – £50. As we have two then it would cost us around £70 to install low flow shower heads on both showers. We would save £204.40 giving a payback of less than 4 months not taking into account the water saved.
Now if we ran a hotel with say 200 rooms (200 showers) and we had an average occupancy of 75% and the average number of people per room was 2, then the annual cost of running high flow showers in these rooms (assuming natural gas heating) would be £17,520 and low flow showers would be £5,256 – a saving of £12,264. Now if you also consider the water costs of these shower (around £35,000 for high flow and £10,000 for low flow) then the savings by installing low flow shower heads becomes quite significant i.e. £37,264 per annum. The cost of installing 200 showers would be around £7000 and so the payback would be just over 2 months.
Now if I operated a hotel or an accommodation based business (B&B or guest house)I would definitely be looking to install low flow shower heads.
Note: If you operate a swimming pool then the benefit is significantly higher by replacing high flow shower heads with low flow, the reason being is that people are likely to use public showers for longer and so the utilisation isn’t likely to be 8 minutes per day but rather hours in the day (very quick payback on swimming pool showers).
So do low flow showers save money – definitely. Are they worth considering – YES, especially if you have a business where people can use your showers without limit. The economics are really a no brainer especially for businesses using electric or LPG/ Oil water heating.