- Autumn Park Industrial Estate, Grantham, NG31 7EJ
- 01476 579058
- Opening Hours: 7:30 am - 4:30pm | Mon - Fri
Energy-efficient, secure and neatly fitted by a local team who treat your home with respect.
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.
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.
From classic flush casements to slimline aluminium, every window is measured, manufactured and fitted for your property — warm, quiet, low-maintenance and built to last.
Make an entrance with composite, aluminium and patio options that combine kerb appeal with proper security and smooth operation day after day.
Bright, comfortable spaces for year-round use. We design, upgrade and replace roofs to improve warmth, light and noise control.
Avanti Windows is a local, straightforward installer serving Grantham and the surrounding villages and towns.
Explore products in real life at Lincolnshire’s only dedicated windows & doors showroom. See full-size installations of composite and aluminium entrance doors, bi-folds, sliders, French doors and every window style (flush casement, sash, tilt & turn, aluminium). Try hardware, compare colours and foils, and view glazing demos (privacy, acoustic, solar-control) side-by-side so you can choose with confidence.
Hands-on security demo: multi-point locks, hinge protection and laminated glass.
Energy corner: feel the difference between standard and A-rated units, warm-edge spacers and trickle vents.
Design desk: bring photos and rough sizes; we’ll sketch layouts and talk budgets, lead times and warranties.
Family & accessibility friendly: step-free access, seating, refreshments and space for prams.
Free parking. Walk-ins welcome; book a 1-to-1 for dedicated advice.
Tip: bring a few photos of your openings (inside and out) and any inspiration shots — it helps us tailor options on the spot.
Most single doors and small window sets are fitted in a day. Whole-house projects usually take 2–3 days, depending on access and the number of openings. We’ll confirm timelines in your itemised quote.
Yes. We take away all old frames, glass and packaging, and we tidy as we go. Where possible, materials are recycled.
A quick home survey gives you the most accurate, fixed price. If you prefer, you can start with rough sizes and photos — we’ll send a guide price, then firm it up after a visit.
Frames, glass units and hardware each carry clear guarantees (up to 10 years, depending on product). Your quote will state the exact cover and terms.
We supply A-rated options with low U-values and the right glazing for your home. If you’re near a busy road, we can also specify acoustic glass for noise reduction.
Yes. Multi-point locking, robust hinges and quality cylinders are standard. Upgrades such as laminated security glass are available for vulnerable positions.
Like-for-like replacements usually don’t need planning permission. Installations are certified to building regulations. If you’re in a conservation area or changing style, we’ll advise before you commit.
If finance is available, we’ll outline it clearly with your quote. Otherwise, staged payments are typical: a small deposit, balance on completion.
We’re based in Grantham and work across Stamford, Sleaford, Newark, Bourne, Melton Mowbray and nearby villages. If you’re close by but not listed, just ask.
