The best window varnishes, compared.
Top pick: Ronseal Interior Matt Clear 750 ml – Highest score in this comparison, 9 out of 10, from 1,099 amazon.co.uk reviews. Best value: Johnstone's Clear Gloss 750 ml – Lowest price per litre in this set, about £11.25 for 750 ml, which is £15.00 per litre. The title says floor varnish. Interior windows are named in the uses line. Updated October 2026.
Window varnish, in UK shopper language, is a clear film for wooden windows, usually exterior doors and windows, and sometimes an interior sill. It is not a fence stain, a floor varnish, or an artist varnish. You tell a relevant tin by the recommended-use line, not by the word varnish alone. Reviews on the outdoor tin report white marks when rain lands, so the one-hour rainproof line is a printed claim. A stated exterior job, a binder you can clean up, a printed coverage rate, and the rain notes in the reviews matter more than the star average. How those checks work is in the [window varnish buying guide](/hub/paints-and-varnishes/window-varnish/sub/window-varnish-buying-guide). Exterior sashes need a product sold for exterior windows.
Window varnish, in UK shopper language, is a clear film for wooden windows, usually exterior doors and windows, and sometimes an interior sill. It is not a fence stain, a floor varnish, or an artist varnish.
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Personal buying guide
Question 1 of 2
Where is the timber?
Ronseal’s interior matt 750 ml is about £16.65, polyurethane, touch dry in 20 minutes, 4.5 from 1,099 reviews. The recommended-use line does not mention windows. One UK review used it on a bathroom window sill and frame after stain, three coats. Other reviews are furniture and interior doors, and several say the matt film has a sheen. A review says the tin forbids floors even though Amazon lists floors. Another reports a white bloom in under six months.
Pros
Cons
Best for: An interior sill or lining if you accept that windows are a review, not the recommended-use line.
Less suitable: Exterior joinery in the rain, or a floor, given the tin-versus-page clash.
Specifications
Common questions
Does the listing say this is for windows?
No. Recommended uses are interior furniture, floors, cabinets and decorative items. One UK review describes three coats on a stripped bathroom window sill and frame.
Can it be used on floors?
The recommended-uses line includes floors. One reviewer says the side of the tin states it cannot be used on floors.
Is it listed as non-toxic?
The page asks. The listing does not answer. There is no certificate number on the listing.
Johnstone’s 750 ml is about £11.25, the lowest price per litre in this set at £15.00, and the material line says acrylic and water-based. Recommended uses name interior windows. The title and the highlight still describe a floor varnish for interior timber floors, and the unit-count field says 1.0 millilitre against a 750 ml volume. The 4.5 from 172 is the same review block as the 250 ml listing, so it is not extra evidence.
Pros
Cons
Best for: An interior wood job, including a window the listing names, when the lowest price per litre matters and you can live with the floor-varnish title.
Less suitable: Bare exterior sashes, or anyone who needs a review sample that belongs only to this size.
Specifications
Common questions
Does this listing say it is for windows?
The recommended-uses line names interior doors, windows, staircases and skirting. The title says gloss floor varnish and the highlight says interior timber floors.
Is it listed as waterproof?
The page asks. The bullets do not say waterproof. They do say non-yellowing and scratch resisting.
Are the 172 reviews separate from the 250 ml tin?
No. This listing repeats the 250 ml review text and the same 4.5 from 172.
Johnstone’s 250 ml is about £10.37, gloss, clear, with a printed rate of 9 m² per litre and low odour among the special features. The title is a floor varnish and the bullets name interior windows. There is no binder and no dry-time figure in the specification. All 34 UK reviews were read. They describe a milky liquid that dries clear, water clean-up, and one leaked tin left upside down. The same review text is in the 750 ml listing.
Pros
Cons
Best for: A small interior wood job, including a window the bullets name, when 250 ml is enough.
Less suitable: Exterior frames, or a buyer who needs the binder in writing.
Specifications
Common questions
Can this listing be used on outdoor wood?
The page asks. Usage says interior. The bullets list interior doors, windows, staircases and skirting, and they do not say yes to outdoor wood.
Does the specification give a dry time?
No. Reviews on the listing mention a couple of hours in December and about 4 hours to recoat when warm. That is review text, not a specification figure.
Is the binder stated?
This listing states no material line. Do not copy acrylic from the 750 ml listing.
Ronseal’s 250 ml Crystal Clear Outdoor matt is the only listing in this set whose recommended use is exterior windows and doors. The shelf price is about £13.03, 4.4 from 262 reviews, water-based acrylic, with a printed rate of 16 m² per litre and a one-hour rainproof line. The same listing’s UK reviews report a clear dry film on oak signs and, repeatedly, white or milky marks when rain hit, plus peeling on a shed after five months in Scotland. The listing does not print a UV sentence or a toy-safety answer.
Pros
Cons
Best for: A small bare exterior window or door when you want the listing that actually names that job.
Less suitable: A large run of sashes, or a buyer who needs the rain claim to be uncontested.
Specifications
Common questions
Is this listing for exterior windows?
Yes. Recommended uses say exterior windows and doors. The material line says water-based and acrylic-based.
Does the amazon.co.uk listing claim UV protection?
No. The page asks about UV. The bullets say it does not yellow like traditional varnishes. They do not say UV.
Do the reviews agree with the one-hour rain claim?
The listing says rainproof in 1 hour. UK reviews also report white dots or a milky film when rain landed, including on hardwood door frames.
The DRW 250 ml satin tin is about £13.79 and the bullets name exterior windows, doors and joinery, with a one-hour rainproof line. There is no coverage, no binder and no star line on the listing. The model string reads like a generic crystal-clear description. That is not evidence the liquid is Ronseal. Rank is 834 in Varnish.
Pros
Cons
Best for: Only if you specifically want a satin exterior tin and will accept a listing with no reviews.
Less suitable: Anyone who wants a review record or a printed coverage rate before buying.
Specifications
Common questions
Does this listing name windows?
Yes. The title and the bullets name doors, windows, garden furniture and exterior joinery.
How many coats does the listing specify?
The page asks. The bullets do not give a number. They also do not say whether painted wood is suitable.
Are there amazon.co.uk reviews on the listing?
No star line and no review text. Country of origin is China. Coverage and binder are not stated.
The figure behind each card is the amazon.co.uk star rating times 20. Ronseal outdoor is 4.4, so 88, shown here as 8.8 on a 1–10 scale. The three tins at 4.5 score 90, shown as 9.0. DRW has no star line, so the score is 0, which means the figure is missing. The top pick is not the highest star score. It is the only listing in this set whose recommended use is exterior windows and doors. The best value is the lowest price per litre, £15.00 on Johnstone's 750 ml. No tin was lab-tested.
Amazon star line
100%The page score is the amazon.co.uk star rating times 20, up to 100. A missing star line scores 0. Review counts do not change that figure. The top pick and the best value use the recommended-use line and the price per litre, not the star score.
You choose window varnish by the recommended-use line, then the binder, the printed coverage and the conflicts on the same page. Stars come last. None of these five tins was lab-tested, and none prints an EN 927 class.
Window varnish, in UK shopper language, is a clear film for wooden windows. It is usually sold for exterior doors and windows, and sometimes for an interior sill. It is not a fence stain, a floor varnish, or an artist varnish. You tell a relevant tin by the recommended-use line, not by the word varnish alone. Exterior sashes need a product sold for exterior windows. Interior boards are a different coating.
A floor varnish, a fence product and an artist varnish can all use the word. The recommended-use line is the split. Johnstone's is titled floor varnish and also names interior windows. Ronseal interior is sold for furniture, and windows appear in one review.
Ronseal outdoor and DRW both print rainproof in one hour. UK reviews on the Ronseal ASIN report white or milky marks when rain landed. Dulux treats two drying days after a short rain as a rule of thumb. Coat dry timber, and leave end grain covered.
The 4.5 from 172 on the 250 ml listing and the 750 ml listing is one copied review block. Adding the counts does not make 344 reviews. Ronseal interior's 4.5 from 1,099 is a separate listing, and it is not sold as an exterior window varnish.
Exterior windows and interior sills take different coatings. Dulux Trade says a fungicidal exterior woodstain is unsuitable on the room side of a frame. EN 927-1 classes windows and doors as stable joinery, meant to limit moisture movement. A shed or fence product is the non-stable class. None of these tins prints an EN 927 class. In this set, only Ronseal Crystal Clear Outdoor Matt 250 ml has a recommended use of exterior windows and doors.
Ronseal outdoor is water-based acrylic, with 16 m² per litre printed. Johnstone's 750 ml is acrylic and water-based, with 7.5–9 m² per 750 ml printed. The 250 ml Johnstone's listing states no binder and prints 9 m² per litre. A 250 ml tin at 16 m² per litre is about 4 m² for one coat before waste. That is arithmetic on the printed rate. The one-hour rainproof line is printed on Ronseal outdoor and on DRW. UK reviews on the Ronseal ASIN report white marks when rain lands.
Three typical situations, each with a recommendation from this comparison.
You want the timber colour and a tin that names exterior windows and doors. Ronseal Crystal Clear Outdoor Matt 250 ml is about £13.03, water-based acrylic, 4.4 from 262 reviews, with 16 m² per litre printed. UK reviews report white marks when rain lands. A 250 ml tin is about 4 m² for one coat before waste.
You are refreshing an interior window the listing names, and the till price per litre matters. Johnstone's Clear Gloss 750 ml is about £11.25, which is £15.00 per litre. The title says floor varnish. Acrylic and water-based are stated. The 4.5 from 172 is the same review block as the 250 ml listing.
You want a polyurethane interior tin with a long review record, and you accept that windows are a review rather than the recommended-use line. Ronseal Interior Matt Clear 750 ml is about £16.65, touch dry in 20 minutes, 4.5 from 1,099 reviews. One UK review used it on a bathroom window sill and frame.
The top pick is Ronseal Interior Matt Clear 750 ml, with the highest score in this comparison (9 out of 10, from 1,099 amazon.co.uk reviews). The best value is Johnstone's Clear Gloss 750 ml at about £11.25, £15.00 per litre. The title says floor varnish. The recommended-uses line names interior windows. The 4.5 from 172 is the same review block as the 250 ml listing.
Ronseal Interior Matt Clear 750 ml
Highest score in this comparison, 9 out of 10, from 1,099 amazon.co.uk reviews.
Johnstone's Clear Gloss 750 ml
Lowest price per litre in this set, about £11.25 for 750 ml, which is £15.00 per litre. The title says floor varnish. Interior windows are named in the uses line.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Public UK sources and maker sheets used for the limits on this page. Prices, stars and review counts are from the amazon.co.uk listings. We did not run a lab test.
This page contains affiliate links to amazon.co.uk with the tag pcuk26-21. If you buy through them, we may earn a commission at no extra cost to you. Prices, stars and review counts are the UK listing lines used for this comparison. We did not run a lab test.
