1. Quote vs Estimate: Understand the Difference
Let’s start with the basics. In the UK:
- A quote is a fixed price based on a full understanding of the work — legally binding once accepted.
- An estimate is a provisional figure that could change, especially if unexpected issues arise.
If your installer gave you a quote for the job — for example, “£5,800 to supply and install three Internorm triple-glazed windows including all finishing” — then that’s the price. If the work hasn’t changed and the product was specified upfront, they are expected to stick to that figure.
2. Specialist Windows Require Proper Planning
At AT-ECO, we supply some of the most advanced window and door systems in the UK — including Internorm, Drutex, Schüco, Reynaers and Uniform.
Some of these systems require:
- Precise structural preparation (e.g. deeper reveals for triple glazing)
- Special fixings or installation methods (e.g. concealed hinges or I-tec securing)
- Lifting gear or two-person handling for large panels
If an installer agrees to the job and then claims mid-way through that the task is more complicated than expected, that’s typically not your problem — it’s theirs. An experienced contractor should have factored in the complexity from the start.
3. When It Is Fair to Adjust the Price
Of course, not every change is unreasonable. Situations that can justify an increase include:
- Unforeseen structural issues, like rotten frames or poorly prepared openings
- Scope changes, such as adding new windows or altering the specification
- Customer-requested upgrades, like changing to a higher performance glass or adding integrated blinds
But price changes should be presented in writing before the extra work begins — not sprung on you as the scaffolding goes up.
4. Misquoting Isn’t Your Problem
A reputable installer understands that quoting is a responsibility. If they underquote because they didn’t fully assess the time or tools required — whether for airtight sealing, precision cutting, or complex frame alignment — they should absorb the cost. That’s the risk they took in submitting the price.
You are not expected to cover shortfalls due to poor planning.
For example, if an installer quotes to fit Internorm windows into existing brickwork and then realises it takes longer because of tight clearances or edge protection — that’s part of their learning curve, not your invoice.
5. Protect Yourself with the Right Questions Upfront
Before work begins, ask:
- Is this a quote or an estimate? (Get it in writing.)
- What does the price include — and exclude?
- Do you have experience with this brand/product?
- Are you FENSA registered and insured?
- What happens if the scope changes?
Reputable companies — like AT-ECO — will answer these questions clearly and transparently. We do this every day.
Why Professionalism Matters
It can feel uncomfortable to push back when a contractor is “nice” or says they’re doing their best. But at the end of the day, professionalism means delivering what was promised at the price agreed.
Friendly doesn’t excuse disorganised. Polite doesn’t justify price hikes. If the job was quoted, and the circumstances haven’t changed, the price shouldn’t either.
Choose Confidence with AT-ECO
We don’t guess our way through installations. AT-ECO works exclusively with certified, experienced professionals who understand the products we supply — from Internorm’s passive house windows to Schüco aluminium sliding systems.
Our quoting process is clear, honest, and designed to eliminate mid-job surprises. Because we believe peace of mind should be part of the package.
