Made-to-Measure Windows & Doors in Grantham

Avanti Windows is a local, straightforward installer serving Grantham and the surrounding villages and towns since 1988.

We’ve built our reputation on three simple things: good advice, quality products, and careful workmanship. Every job starts with a proper survey, not a sales pitch. You’ll receive a clear, itemised quote and realistic lead times.

On installation day, our fitters protect floors and furnishings, work cleanly, and take away all old frames and glass. If you ever need us after the job, you’ll speak to the same friendly team who fitted your home — not a call centre.

WHY AVANTI

Why Homeowners Choose Us

Lower energy bills: A-rated performance with the right glazing for your home.
Built for security: Quality frames, hardware and locking systems as standard.
Tidy, fuss-free installs: Polite fitters, dust protection, and everything cleaned before we leave.

Avanti Windows is a local, straightforward installer serving Grantham and the surrounding villages and towns since 1988.

    
 
 
      Trustindex verifies that the original source of the review is Google. I have been using Avanti for 35 years and the service and product quality is amazing!
  
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   Will mcintosh 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. Cannot recommend Avanti enough!!
Amazing service from start to finish.
The whole team were friendly and professional.
Great job and have told all my family and friends if they ever need a job doing, to give them a call
  
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   Natalie Buxton 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. We had nine blown windows, called a couple of window companies to try and get the best price and these guys were the only ones who got back in touch with us. We weren't willing to wait around so went with them and I'm glad we did. They came out, took the measurements and ordered the glass.

I was advised the glass could take about four weeks which was fine. Less than a week later I got a call asking if there was any chance they could come later today to fit our new windows!

They came round and had them all replaced in about an hour!!
For the first time since we've moved into our house we have been able to see properly out of our window!

Thank you for the professional and prompt service! I would recommend.
  
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   Lisa Knight 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. We have this week had our windows installed courtesy of Avanti Windows Grantham.
From start to finish we have had excellent service. I knew I was in safe hands when I met Richard who came out originally to measure up and quote, but to be honest everyone we have dealt with from Richard through to the fitting team have been spot on. Very professional.
We did get quotes from other well known window suppliers but the out dated sales tactics and tedious process put us off. There was none of that with Avanti….
It was so easy. I would highly recommend them. I’d give 6 stars if I could👍🙏
  
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   MARK GOODE 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. Amazing firm and very professional. They’ve done a great job In replacing our conservatory roof for a solid one. Punctual everyday and end result it brilliant. Highly recommend
  
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   George Pim 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. Avanti delivers an outstanding service. I had a new glass roof fitted on my conservatory and the team also refurbished the whole conservatory and made it look like it was new. Fantastic job, exceeded my expectations. I have no hesitation in strongly recommending this company. A big thank you to the whole team at Avanti, a great bunch of guys!
  
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   Douglas Howcroft 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. Brilliant company. Quality windows. Staff really friendly and helpful.
  
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   Chris Jones 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. Absolutely over the moon with my windows and doors, service and fitting is top notch!! We will be having replacement windows from them in the future!!
  
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   Toni Blakey 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. A patio door leaked because they "forgot to put in drain holes". Ahe door got fitted by "trimming" the opening by wacking it with a lump hammer (even though the builder was on hand with a diamond saw), the windows came scratched and the external paint could be removed with a finger.  I saw they hadn't sealed in the window frames and asked why not.  Apparently they don't carry sealant!?!?

They all got taken out and my builder rebuilt the door opening.
  
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   Sheila and Peter 
 
 
 
 
     Trustindex verifies that the original source of the review is Google. Tony and the team were very professional throughout the whole process. The fitters had to install all new windows and doors and have completed to a high standard. They have been very accommodating with my timescales and would highly recommend. Thank you!
  
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   Evie English