Building energy myth buster
Myth: Contractor savings estimates are always reliable
Contractor proposals can be useful. But the savings should still be checked.
A contractor may provide a clear proposal, an estimated saving, a payback period and a carbon reduction figure. That can be helpful, but the estimate is only as strong as the assumptions behind it.
Before committing to energy projects, organisations need to understand whether the proposal fits the building’s real energy use, operating pattern and priorities.
The reality
Savings estimates are only as good as the assumptions behind them
Contractor proposals can help organisations understand possible solutions, costs and implementation routes.
But estimated savings should not be treated as automatic proof. The calculation may depend on assumptions about running hours, energy tariffs, existing performance, occupancy, control settings and future use.
The proposal may still be worthwhile. But it should be assessed against the building, not just the product.
Where the myth goes wrong
A contractor proposal may not identify the real priority
Contractors often focus on the solution they provide. That solution may be valid, but the building may have a different or more urgent energy issue.
Generic assumptions
Savings may be based on standard operating hours or typical equipment use rather than the building’s real data.
Wrong baseline
If the starting energy use is misunderstood, the claimed saving and payback may also be misleading.
Solution-led thinking
A lighting, solar, heating or controls contractor may focus on their own measure rather than the whole building.
Avoidable waste ignored
Poor schedules, night-load or control issues may need fixing before a larger investment is properly assessed.
Payback overstated
Small changes in tariffs, hours of use or expected performance can make a large difference to payback.
No post-project check
Without follow-up data review, the organisation may never know whether the estimated savings were achieved.
Baseline before savings
Before accepting the saving, understand the starting point
Savings are usually calculated against a baseline. If the baseline is wrong, the estimate may be wrong too.
For example, a building may appear to offer a strong payback because current energy use is unusually high. But that high use may be caused by poor schedules, out-of-hours operation, heating and cooling conflicts, or a fault that should be fixed first.
A building energy review helps establish what the building is doing now, what demand is necessary, and which part of the energy use may be avoidable before larger projects are chosen.
Proposal review
Contractor proposals need building context
A contractor proposal may include a useful solution, but it should be connected to the way the building actually operates.
Without that context, it is difficult to know whether the savings are realistic, whether the measure should happen now, or whether another action should come first.
The aim is not to block investment. The aim is to make investment better targeted and easier to justify.
A practical review can check:
- whether the savings assumptions are reasonable
- whether the baseline matches real energy data
- whether avoidable waste should be reduced first
- whether the proposal fits current occupancy and operating hours
- whether the measure is solving the right problem
- whether claimed payback is realistic
- how savings could be checked afterwards
The practical next step
Use independent energy review before committing to larger projects
Building Energy Audit + Proposal Review
Oxford Energy Services helps organisations make better energy decisions before committing to contractor-led work.
A fixed-fee Building Energy Audit can identify the real energy priorities for one building. Ongoing Energy Management Support can help sense-check contractor proposals, review savings assumptions, compare options and check whether changes deliver results.
What proposal review can look at
A practical check before relying on savings estimates
A proposal review helps connect contractor claims to the building’s actual data, operation and priorities.
Baseline
Check whether the starting energy use is realistic and properly understood.
Energy data
Use electricity, gas and half-hourly data to test the proposal assumptions.
Operating hours
Review whether assumed run hours match the building’s real use.
Controls
Check whether schedules, settings or overrides may be affecting the saving.
Night-load
Identify whether out-of-hours use should be addressed before investment.
Measure fit
Assess whether the proposed solution is the right measure for the building.
Payback
Sense-check the claimed payback period and the assumptions behind it.
Alternatives
Consider whether other actions should happen first or alongside the proposal.
Verification
Plan how savings will be checked after the work is completed.
Next decision
Clarify whether to proceed, revise, delay, investigate or compare further options.
The outcome
Better confidence before committing to energy projects
You receive practical support to help judge whether contractor proposals are realistic, well-targeted and worth progressing.
- Clearer understanding of savings assumptions
- Better evidence before approving spend
- Support for comparing contractor options
- Reduced risk of solution-led decisions
- A stronger plan for verifying results
This is useful if
You have a proposal but are unsure whether the savings are realistic
- You are reviewing quotes for lighting, controls, heating or solar PV
- You need to sense-check claimed savings or payback
- You want evidence before committing to capital spend
- You have several contractor proposals saying different things
- You want to know what should happen before the project goes ahead
Common questions
Questions organisations often ask about contractor savings estimates
Are contractor savings estimates always reliable?
Not always. They can be useful, but they depend on assumptions about baseline energy use, operating hours, tariffs, occupancy, equipment performance and future use.
Does this mean contractor proposals are not useful?
No. Contractor proposals can be very useful. The point is that they should be checked against the building’s real energy data, operation and priorities before decisions are made.
Should we review proposals before or after an audit?
Both can be useful. An audit gives a strong baseline and helps identify priorities. Existing proposals can then be reviewed against that evidence.
Can you help check savings after the work is done?
Yes. Energy data can be reviewed after changes are made to see whether consumption has reduced and whether further action is needed.
Free 30-minute discussion
Need help reviewing an energy proposal?
Start with a practical conversation. Oxford Energy Services can help you understand whether your proposal, savings estimate or payback calculation needs independent review before you commit to the next step.
Contact Russell
Email:
russ@oxfordenergyservices.co.uk
Phone:
+44 (0)7803 397 549