Homeowner Blog

Why is Your Roof like an Empty Buy-to-Let Flat?

Tok Charles · 22 May 2024

If your buy-to-let flat were empty, it would be your absolute priority to get a tenant in – because once it’s occupied, it’s effortless passive income. Your roof is the same, it has the potential to be turned into an energy-generating business. Every day that it’s not got solar on, you’re losing money on expensive electricity bills, and you’re missing out on making additional money from selling your solar generation back to the grid.  

Here’s a table showing estimated weekly spend depending on annual electricity consumption: 

Annual Electricity Consumption (kWh)   

Current Price per kWh (p/kWh)  

Weekly Electricity Spend        (£)  
















Since Spirit started installing in 2010, the price of electricity has increased by 2.5 times, and the effective cost of solar panels has halved - which is why your roof has become more valuable every year. It’s like buy-to-let flat grew – for free – on the roof of your house.  

Increasingly, we get people coming back to us that we quoted several years ago – that didn’t proceed with the installation at the time. Delaying a solar system is an expensive decision, even for just a month, that’s costing the average household £100+. That’s a Starbucks coffee & croissant every day!  

One of Spirit’s residential designers said the following: "We get a lot of clients that request a quotation from Spirit and then wait 3-4 weeks for quotes from other installers to land in their inbox. While it’s always prudent to get multiple quotes, it’s costing you upwards of £100 waiting for installers to get round to providing a proposal. That’s why we always look to respond to enquiries within a couple of days; same day if possible."  

At the moment, most solar systems are paying for themselves within 5-6 years, on average, increasing to 7 years if you include a battery. Solar panels are warrantied for 25 years as standard, meaning you’ll get nearly 20 years’ worth of free electricity. If you decide to sell the house, you should be able to add on the net present value of the system to the value of the house. Spirit can provide a certificate for the present value of the system when you come to sell it.  

So, get your solar PV system installed and get on with saving money. Then, when it’s installed, get a guilt-free Starbucks breakfast every day (other premium coffee shop brands will do). 

Topics: Battery storage, Solar PV