New builds operate slightly differently from existing homes when it comes to electricity and gas contracts. Many new homeowners do not realise they are automatically placed on a default tariff — often one that is not the most competitive.
In this guide, we will explain from first principles:
How energy supply works in new build homes
What a deemed contract is
When you can switch energy supplier
How to compare energy tariffs for new builds properly
Common mistakes to avoid
Our goal is to ensure you do not overpay simply because your property is brand new.
How Energy Is Set Up in a New Build Property
When a developer completes a new build property, they arrange an initial electricity (and gas, if applicable) connection.
This means:
A supplier is assigned to the property
A meter is installed
The property is registered on the energy network
However, this does not mean you are on a competitive energy deal.
In most cases, new homeowners are placed on what is known as a deemed contract.
What Is a Deemed Energy Contract?
Deemed Contract
A deemed contract is a temporary energy agreement applied automatically when:
You move into a property
You have not actively chosen a supplier
Energy is already being supplied
Under a deemed contract:
You do not choose the tariff
Prices are often higher than fixed deals
There is usually no fixed term
You can switch at any time
Deemed tariffs are designed as a temporary holding arrangement — not a long-term solution.
This is why energy comparison for new builds is so important.
When Can You Switch Energy Supplier in a New Build?
In most cases, you can switch as soon as:
You become the legal occupier
You have taken meter readings
You have informed the existing supplier
You do not need to wait months.
Switching energy supplier in a new build:
Does not interrupt supply
Does not require rewiring
Is fully regulated
Usually takes 2–5 weeks
The sooner you compare energy deals, the sooner you move off the potentially expensive deemed tariff.
Why New Builds May Have Different Energy Profiles
New build homes are typically:
Better insulated
More energy efficient
Built to modern building regulations
Equipped with smart meters
Fitted with energy-efficient boilers or heat pumps
This means:
Electricity and gas usage may be lower than older properties
Heating systems may differ (e.g., electric heating, air source heat pumps)
Because of this, estimating annual usage accurately can be challenging in the first year.
Energy comparison should be based on projected consumption and adjusted later when real data becomes available.
How to Compare Energy Suppliers for a New Build
At Utility King, we recommend following a structured process.
Identify the Current Supplier
The developer or letting agent can usually provide this.
If not, you can:
Contact your local electricity network operator
Use national meter registration services
You need to know who is currently supplying the property before you can switch.
Take Opening Meter Readings
Record electricity and gas meter readings on the day you move in.
This ensures:
You are not billed for previous usage
Your starting balance is accurate
Accurate data protects you financially.
Understand Your Heating System
New builds may use:
Gas central heating
Electric heating
Heat pumps
Underfloor heating
Solar panels
If your home is electricity-heavy (for example, using a heat pump), unit rate becomes especially important.
If you have solar panels, you may also need to compare export tariffs.
Compare Total Annual Cost
When comparing energy deals for new builds, focus on:
Unit rate
Standing charge
Estimated annual cost
Payment method
Because new builds may have lower energy usage, standing charges may represent a larger percentage of your total bill.
Always compare total annual cost — not just unit rate.
Choose the Right Tariff Type
You will typically choose between:
Fixed Energy Tariff
- Locks in rates for 12–24 months
- Provides budgeting certainty
Standard Variable Tariff (SVT)
- Flexible
- No fixed end date
- Rates may change
Many new homeowners benefit from locking into a competitive fixed deal shortly after moving in.
Common Mistakes in Energy Comparison for New Builds
Staying on the Deemed Tariff Too Long
This is the most expensive mistake. Deemed rates are rarely competitive long-term.
Ignoring Standing Charges
Low-usage homes can be disproportionately affected by high daily charges.
Forgetting to Register for Smart Export Tariffs
If your new build includes solar panels, you may be eligible to earn money by exporting unused electricity.
Not Updating Usage After Year One
Your first year's usage may differ from estimates. Review your tariff after 12 months with real data.
Is Switching Energy Supplier Safe in a New Build?
Yes.
Switching:
Does not disrupt supply
Does not void building warranties
Does not require developer permission
Is protected by regulation
Your electricity and gas connection remain unchanged.
Only your billing provider changes.
Utility King's Perspective
At Utility King, we believe new homeowners should treat energy setup as a priority — just like broadband or insurance.
New build properties are often placed on temporary deemed contracts that are not designed for long-term value.
The best approach is:
Register with the existing supplier immediately
Take accurate meter readings
Compare energy deals within your first month
Lock in competitive pricing if appropriate
Energy comparison for new builds is about acting early.
The earlier you review your tariff, the sooner you stop overpaying.
Frequently Asked Questions
Can I switch immediately?
Yes, once you are the legal occupier and have registered with the existing supplier.
What is a deemed contract?
It is a temporary default tariff applied automatically when you move into a property.
Are deemed tariffs more expensive?
They are often less competitive than fixed energy deals.
Do new builds have lower bills?
Generally yes, due to improved insulation and energy efficiency.
Should I choose a fixed tariff?
Many homeowners prefer fixed tariffs for budgeting stability.
What if I have solar panels?
You may need to compare Smart Export Guarantee (SEG) tariffs to receive payment for exported electricity.