Before you book
What you need to know.
- Review peak use and recovery needs before choosing capacity.
- A replacement can need connection or access work even when it stays in the same location.
- Changing fuel type, technology or position needs a separate assessment of the installation scope.
- Compare the fully installed system, including removal and any other trades, rather than the unit price alone.
On this page
Check whether replacement is the right next step.
If a system has developed a fault, identify what failed before replacing it. A leaking valve and a failed storage cylinder have different repair options. Where replacement is justified, the existing model and fault history help explain what the new system needs to improve.
Replacement is also an opportunity to review changed demand. More occupants, altered bathrooms or a new daily routine can make the original arrangement unsuitable. Tell the plumber whether the old system previously performed well or was always short of hot water.
Choose capacity around the busiest normal use.
Household size helps, but simultaneous demand and recovery are more useful than headcount alone. Describe the number of showers used close together, bath use and other regular hot-water demand. A storage unit needs enough usable supply and reheating opportunity for that pattern.
Continuous flow output needs to suit the required temperature and outlets in use together. Storage litres and continuous flow litres per minute aren't directly interchangeable. Sizing should consider the product's performance information and conditions at the property.
Scroll sideways to read every column.
| What to discuss | Why it matters |
|---|---|
| Morning and evening shower pattern | Identifies the peak period the system needs to support |
| Baths and simultaneous outlets | Shows demand that headcount alone can miss |
| Existing energy supply | Affects suitable systems and required connection work |
| Available space and access | Determines siting and equipment removal |
| Current performance | Separates an undersized arrangement from a recent fault |
| Future property changes | Avoids selecting around a layout about to change |
Assess the site before ordering the unit.
The new unit has to work with the property's pipework, supply and physical space. Connection positions, valves, drainage, support and service access can change between models. A system fitting through the doorway doesn't establish that the installation is suitable.
Gas equipment needs appropriate supply capacity and siting. Electric work needs the required qualified trade and a suitable supply arrangement. Moving the unit or changing type can add work beyond replacing existing connections, so discuss the scope before purchasing equipment independently.
Access for removing the old unit matters as much as bringing the new unit in. Describe stairs, narrow cupboards, fenced side passages and shared areas. For strata, establish the approval contact and any restrictions on altering external equipment or common services.
Compare like-for-like with a deliberate change.
Replacing with a similar system can limit the changes needed, but the installation still needs assessment. A different arrangement may better suit demand or available space, while requiring new connections or work by other trades.
Use the complete cost and practical effect in the comparison. A lower product price can be outweighed by installation changes; a more expensive model needs a reason tied to the household. If you're considering technology beyond the existing gas or electric setup, confirm the service scope and suitability before ordering.
Running-cost estimates depend on usage, energy prices and the selected product. Government hot water guidance can help frame the options, while your retailer can confirm the available tariff. Don't treat a generic savings figure as a quote for your property.
Make the full installation quote clear.
A useful quote identifies the unit and the work required to install it. Supply, plumbing connections, required fittings, other trade work and removal of the old unit should be clear. If moving the system, include the pipe route and any property work affected.
Ask how additional work will be approved if the existing connections need more attention than expected. Confirm the product terms and workmanship coverage separately. Clear inclusions help compare alternatives without discovering after booking that essential work was excluded.
- Proposed brand, model and capacity
- Installation position and any relocation work
- Water, gas and electrical work included
- Required valves, fittings and discharge arrangements
- Access, removal and disposal of the old system
- Any separate trade or property work
- Commissioning, handover and supplied records
Plan the interruption and installation day.
Hot water will be unavailable during parts of the changeover. The cold supply may also need isolation for the work. Explain essential household or business requirements and arrange the person who can provide access and approve decisions.
Installation timing depends on assessment, equipment availability and the work required. Once a booking is agreed, keep the route and working area clear. Don't disconnect or move the existing unit yourself to prepare.
Review the existing installation
Confirm demand, equipment, connections and access.
Agree the replacement scope
Select a suitable unit and identify the full installation work.
Arrange access and interruption
Coordinate occupants, authorised contacts and any required trades.
Install and commission
Complete the agreed connections and relevant operating checks.
Explain normal use
Provide operating information, recovery expectations and the records supplied with the job.
Keep the handover information for future service.
Retain the invoice, model and serial number, owner's information and relevant compliance records supplied with the installation. Those details help identify the system for maintenance and any product enquiry. Ask which controls are intended for normal owner use.
A new storage system needs time to establish its hot supply. The handover should explain what to expect, any operating settings and how to report a problem. Follow the maintenance instructions for the installed model rather than a general schedule for a different system.