Thermashield Windows & Maintenance Ltd

Thermashield Windows & Maintenance Ltd

Trustys Member Since 2016

What we do

Ronnie has over 30 years experience.
Worked for original Thermashield company until owners retired and in 2010 started on his own as Thermashield – same name but smaller company.

Based at their factory in Cumbernauld they are perfectly situated to serve the Central belt of Scotland. Meaning you’ll have the peace of mind that you’ll be dealing with an easily accessible local company.

All windows, doors and conservatories come with a 10 year guarantee as standard. So, in the unlikely event of any issues, the Maintenance Division are on hand to carry out any remedial work.

Thermashield Windows & Maintenance also offer a wide variety of roofline and cladding options.

All installers are highly trained.

Maintenance Division are available to carry out a wide variety of repairs on all types of windows, doors and conservatories including:

  • Repairing/replacing smashed or broken glass
  • Changing door panels
  • Changing single to double glazing
  • Locks, handles & hinges
  • Conservatory repairs
  • Roofline repairs
  • Draughts re-sealing and more!

Visit Thermashield Windows & Maintenance website for more details about what Ronnie and the team can do for you!


All of Thermashields windows are manufactured and fitted to the highest standards which guarantees outstanding weather performance, compliance with security standards and excellent durability.

uPVC casement windows
‘Verticle Sash’ or ‘Georgian style’ windows
Tilt and Turn windows


Thermashield Windows & Maintenance offer a free design service and will carry out all manufacturing work in our factory. This allows us to ensure that your conservatory is designed, manufactured and installed exactly to your specification.


Thermashield Windows & Maintenance offer a wide selection of high quality, secure and stylish doors including:

  • Composite doors
  • uPVC doors
  • French & Patio doors

Vandal Shield

Vandal Shield unobtrusively protects property and glazing by preventing access to windows. With Vandal Shield there are no unsightly iron bars, steel mesh or expanded metal which may not even protect the glass.


Peter Barrowman, Stenhousemuir said on 17/03/2022:
Fantastic service, no pressure when giving us a quote, price was amazing and did 8 windows and two doors in 2 days. Quality is great and I highly recommend them for any windows and doors that you need.

Verified Customer, Bo’ness said on 30/01/2022:
I am really happy with the work Ronnie and his team did in my home and appreciated their ‘can do’ attitude. I would ask them to do more work in the future.

Gillian Steele, Polmont said on 25/01/2022:
We are delighted with the work done by Ronnie and his team. It was completed quickly and tidily. Minor snagging was dealt with speedily, nothing was too much trouble. We would highly recommend Thermashield. Indeed we already have!

Susanne Marshall, Bathgate said on 11/01/2022:
Have had Ronnie out for a few jobs over the years, including recently fitting French doors and a new back door for us.  Nothing is too much trouble. They arrive when they say they will, and the work and Doors are of high quality. Not many workers left like these guys. Very reliable and pricing is reasonable. Won’t go anywhere else!

Dr Ajith S Nair, Glasgow said on 29/11/2021:
Exceptional workmanship and Quality that speaks for itself. Changed my doors and windows. Work was completed to excellent standards and the whole area was left spotless. True Professionals the workmen were. Highly recommended.

Sylvia Russell, Renfrew said on 21/11/2021:
I have just had two windows and patio door and front door replaced by Ronnie & his team. Quality of work was excellent and the team arrived early on both days and were meticulous with their work. Would highly recommend this business as Ronnie was very helpful and the price was very good for the quality of the work and product.

C Schofield, Bonnybridge said on 08/11/2021:
I contacted Scott on Friday and even though busy, he made time on Monday night to fit a new oven for me. Quick work that was much appreciated! Would recommend.

Lynn Hunter, Grangemouth said on 20/10/2021:
Windows replaced in rental. Despite delays due to supply of materials Ronnie kept tenant advised. Communication was good. Job was top quality – no damage to decor. Very competitive price. Happy to have used Ronnie and his team again.

I Galloway, Cumbernauld said on 12/08/2021:
An excellent job in replacing five windows by Ronnie and his team. Very professional throughout, absolutely no problems with regards to timing or communication. Would highly recommend this company.

A Johnston, Stirling said on 19/07/2021:
Ronnie and his fitter provided a very clean and professional service. My large replacement window was fitted into the existing internal hardwood frame. It is an excellent fit. First class communication and finished job. Would recommend.

Jax & Al, Bearsden said on 06/07/2021:
Very efficient, professional and exceptional service at every stage of the purchasing process to completion of work. Given time to assess any adjustments which were required, but this was unnecessary as work perfect.

CW, Fintry said on 02/07/2021:
I have bought recently a new back door through Thermashield. The process was very easy and quick, and I am hugely pleased with the door. Ronnie is owner of the business and delightful, as are his men. My door is good quality and Thermashield were very professional in fitting it. I would recommend Thermashield without hesitation.

Mr & Mrs Royce, Falkirk said on 15/06/2021:
Thermashield replaced all our windows and our front door. We were very pleased with the results. From the initial consultation to the final inspection everything was handled in a professional manner.  When we arranged the initial consultation, Ronnie arrived right on time, asked us what we wanted and made helpful suggestions. We never felt rushed or pressured into making a decision. The window fitting team were efficient, industrious, polite and very tidy. They ensured all soft furnishings and carpets were covered and took great care when in the house. They even hoovered the carpets and cleaned the windows when they finished!  Great product, great tradesmen & great customer service. What more could you want? We would highly recommend Thermashield.

Martin, Cumbernauld said on 13/06/2021:
Very pleased with the service, from start to finish. Ronnie made the process easy and the installers were brilliant. And a great price.

Jim Thomson, Falkirk said on 15/05/2021:
The Thermashield team were tremendously efficient, friendly and professional. Their work was outstanding and happily they cleaned up the house before they left. Their price for the job was extremely competitive. We are delighted with our new window and patio doors.

Verified Customer, Polmont said on 11/03/2021:
Second time we have used Thermashield, having been recommended by a neighbour who has also used them a few times. Really can’t praise them enough. Great value for money and fantastic service. Would have no hesitation recommending them to friends and family.

David Stewart, Bo’ness said on 16/12/2020:
Thermashield replaced an old leaking conservatory with a new one with a tiled roof. The work was carried out quickly and to a very high standard with no mess left. The cost was very competitive compared to other quotes I got.  Overall, I am delighted with the installation, and would highly recommend them. A big thanks to Ronnie and his team.

Fiona Tweedie, Culross said on 13/12/2020:
A very professional company. Due to me having to change my plans, Ronnie had to visit a few times prior to starting work but he was most helpful, and nothing was too much for him. Work started promptly at the time stated and the men worked diligently until completed. Extremely pleased with the resulting secondary glazing.   I would thoroughly recommend this company.

Lynn Hunter, Grangemouth said on 25/11/2020:
Top marks to Ronnie and his team for fitting double glazed windows at one of my rentals. Beautiful job and no damage at all to the decor. Very competitive price and great quality. Fitters were superb and did the full job in one day minimising the disruption to my tenant who is over the moon at the difference in heat retention and noise reduction. No hesitation in recommending Thermashield.

Mrs Hunter, Grangemouth said on 16/10/2020:
We ordered a composite door with double glazing side panels. The door was installed & fitted within a couple of hours, the fitters were professional, friendly & thorough in terms of the fit and finish. We are over the moon with our door it looks fantastic and most importantly it has made a huge difference to our hallway keeping heat in and cold out! We rang around for quotes and feel that we got a very fair price for the quality of door we ordered. Ronnie even came round after the door was fitted to check if we were happy with the job – just fantastic service all round. No hesitation recommending.

C MacDonald, Falkirk said on 10/09/2020:
Very happy to recommend this company. My patio window got smashed at the time all companies contacted were going into temporary closure due to COVID-19. Ronnie answered the call & very kindly came out to check if in anyway, he could help but unfortunately, he did not have the glass required. I decided when window companies opened again it would be better due to age to replace completely with new French Windows. I got prices from companies recommended to me, but decided to contact Ronnie as well & was given an excellent price. Feedback like this actually confirmed to use his company. Great service throughout.

Stephen Dibdin, Skinflats said on 04/09/2020:
9 windows installed in less than 2 days. Dust sheets put down inside and outside, hoovered and cleaned up before leaving. Very professional and courteous. Thank You.

C Capes, Falkirk said on 04/09/2020:
Excellent company to deal with. Great price, fitters were professional, efficient and tidied up after they had finished.  Nice touch is the owner comes back to check on the installation and make sure everything is ok. Would definitely recommend to others and will use this company again.

John Duffy, Cumbernauld said on 25/08/2020:
We just had a return visit from Ronnie to replace a further 2 windows.  I have to say that the level of service from Ronnie and his fitters was excellent.  The fitters arrived on time were excellent workers and very courteous and cleaned up and hoovered everything leaving no mess whatsoever.  I would give the entire company 5* and would not hesitate to recommend them as I will use them in the future if I need anything done.

Alex Neilson, Glasgow said on 22/07/2020:
I am spectacularly happy with the service from Thermashield. The whole process was fast and highly professional, and the windows are excellent quality.  Their aftercare has been very good and the 10- year guarantee is very reassuring.  Would recommend them to anyone. 5*****

Yvonne Robertson, Falkirk said on 29/03/2020:
I waited to give feedback to make sure there was time to see benefits.  The company did all they could to tailor the windows to our needs as the windows are made by the company and not elsewhere.  No other company was able to do this, and it meant that although not our cheapest quote (but not a huge price difference from other companies), these were the guys we wanted to work with. Communications were good throughout and on the day of fitting, there was an extra fitter so the job could be done in one day instead of over 2 with it being a weekend. The windows are stunning and couldn’t be happier!

Alan Walker, Glasgow said on 30/01/2020:
Alan & Yvonne Walker would highly recommend Thermashield Windows for their professionalism & workmanship on the installation of our windows.  They were courteous, clean, tidy and safe from the start to the finish of the job.  To Ronnie and the boys all the best.

Brian Burrell, Falkirk said on 19/12/2019:
OK, we have all heard the reputation of most double-glazing companies, and I had a few quotes, so I had some ridiculous figures to compare.  I wanted 9 windows. With some of the quotes I assumed they were building an extension…. So, I was lucky to find Thermashield, affordable, good quality and even with a slight glass problem it was sorted within 24 hours, a professional, friendly company. Thoroughly recommended.

Colin & Janet Kidd, Polmont said on 28/10/2019:
Thermashield replaced our leaking conservatory. We had an old lean-to style which they replaced with a much more energy efficient one with a solid roof.  Huge difference in temperature already. Team were very efficient, clean, tidy and arrived when they said they would. Ronnie came along regularly to check we were happy. Would use them again and would highly recommend this company.

Verified Customer, Bargeddie said on 03/10/2019:
Installation of replacement double glazed windows.  Efficient service.  Work completed to a high standard.  No mess and very pleased with new windows.  Reliable and courteous.

Verified Customer, Cumbernauld said on 02/10/2019:
Thermashield replaced my old draughty windows and doors. They did a fantastic job, the house is noticeably warmer and quieter, they came when they said they would, cleaned up afterwards, great price – highly recommended.

Douglas Thompson, Dunfermline said on 10/09/2019:
Absolutely delighted with our new composite doors – which we designed ourselves using Thermashield’s Door Designer tool.   The guys were on-time, friendly and did a fantastic job. Excellent value too. Highly recommended!

R Wright, Grangemouth said on 20/08/2019:
Really delighted with complete job from start to finish.   Clean, tidy, good time keeping and pleasant workers including boss.  Would highly recommend this company.

L McQueen, Denny said on 17/07/2019:
No hard sell , reasonably priced, and windows were fitted in a week from measure.  Tradesmen clean and tidy good workmanship.  Would definitely recommend.

J D Morrison, Grangemouth said on 11/07/2019:
Replaced doors, truly excellent job.

Mr Laing, Stenhousemuir said on 15/06/2019:
Doors, windows, Velux and sofets.  Have used this company several times and would recommend them.

James Scott, Carron said on 05/06/2019:
Installed 10 windows and new door and were superb.  Hard working, efficient, neat and tidy. Couldn’t be faulted.  Highly recommended.

Darryll Morrison, Grangemouth said on 28/05/2019:
Ronnie and his team of installers were just a joy to have take on my windows and doors installation.  Their work ethics and workmanship were just first class.  Amazing job from quote to completion.  Thank you.

Mrs Hammond, Glasgow said on 08/05/2019:
I have recently had new windows and doors fitted and everything that was done was lovely.  The men were very mannerable and always here on the dot and their work was really good.  Everything was absolutely spot on from start to finish and I would definitely recommend Thermashield.

Verified customer, Larbert said on 22/04/2019:
We had new windows put in our house in February.  Ronnie turned up when he said he would, gave advice where needed and did a great job.  Really happy with the replacement windows and with service provided.

Jim Browning, Kirkintilloch said on 16/04/2019:
Have previously used this company and recently have had a full window replacement carried out by them.  As usual more than satisfied with every aspect of job.   Quality of product excellent.  Planning, installation, preparation and cleanliness all first class.  Special mention to Brian for attention to detail and Ronnie for organising contract.  Would certainly recommend.

Stephen Cameron, Falkirk said on 07/04/2019:
Happy to recommend Ronnie and his team who did an excellent job installing a new front door and windows to the front of my house.   Turned up on time and didn’t leave any mess when they left. Won’t hesitate to use again in the future.

Jane Cunning, Cumbernauld said on 29/03/2019:
Double glazed unit in bedroom window replaced.  Great service, clean and tidy workmanship and good price.

Mrs Shovlin, Falkirk said on 15/03/2019:
I am really delighted by quality of the windows and the workmanship was first class.  They turned up when they said they would and you would never have known they had been in the house, they were that tidy.  I would highly recommend them and will be letting all my friends know they shouldn’t look any further than Thermashield.

Isobel White, Glasgow said on 04/03/2019:
I would highly recommend this Company, I have already had neighbours remark on my new windows and door.  I had seven windows and a new door fitted by this Company.  This Company transformed my home and brought light into every room.  The new windows and new door have changed my home significantly. I phoned this Company and Ronnie McLean the Owner called at my home and advised me of the different types of windows and doors I could choose.  The advice received put me at my ease. Their catalogue has many styles to choose from.  I was given a quote straight away for what I chose.  I was told when the window fitters would arrive to start the job and they arrived on time. They finished the job when stated. I paid what I was quoted. The joiners who worked on my new windows and door, Andy and Brian, were highly skilled courteous workers who left my home neat and tidy when they finished. I am absolutely delighted with this Company.

Mark R, Brightons said on 07/02/2019:
Exceptional service from friendly staff.  Great communication throughout.  Fair price – some 33% of other quotes provided.  On time and done as they promised.  No mess left.  A tidy and complete finish.  I would not hesitate to recommend.

Tom Hutchison, Glasgow said on 12/11/2018:
A five star service.  They did a first class job designing and fitting to new windows in a difficult situation.   A very high standard of workmanship and very reliable.  Brilliant – I am very happy and would highly recommend them.

Natasha Kumar, Cumbernauld said on 12/11/2018:
A total of six windows (2 double-glazing and 4 single-glazing) were asked to be replaced as part of the Scottish Gov Climate Challenge Funded project.   The work was carried out very quickly and Ronnie made an extra effort to ensure our constricted timelines were catered to. The team were polite and on-time and had carried out the work efficiently and to a high standard. Additionally, they did a fantastic job ensuring that our centre was left in a clean condition once the job was completed.   Would highly recommend their services to both domestic and commercial customers.

Lynn Hunter, Grangemouth said on 08/11/2018:
Full credit to Ronnie at Thermashield.  It’s how well a business reacts when something goes wrong that sets them apart from the rest.  A few months after having a new upvc front door supplied and fitted by the team I discovered condensation gathering between the panes of glass in one section. I called Ronnie who got on the case right away. He came out to identify the problem and ordered a replacement unit. Unfortunately when it arrived from the supplier it was damaged and had to be re-ordered. Ronnie kept me updated all the way and he replaced the damaged window this afternoon. It’s never nice having to complain but so much easier when the business owner is as positive and helpful as Ronnie. I’m a happy customer 😊

Shona W, Cumbernauld said on 07/11/2018:
Thermashield carried out double glazing work at our property recently.  The work was done to a really high standard and the team tidied up every night before they left.  We are extremely happy with the work and would not hesitate to recommend Thermashield to anyone.

Lillias Wright, Grangemouth said on 18/10/2018:
We had a new external door fitted by the above company and we were delighted with the way the job was carried out, and with the tidiness of the workmen, and we would definitely recommend this company.

Ewan Graham, Larbert said on 03/09/2018:
Phoned Ronnie at Thermashield to enquire about repairing two double glazed window hinges on a rental property.  He was at the property within a few days and got back in touch with the quote. The repair was carried out soon after. A very quick and reliable service from Ronnie and his team.

M Morrison, Falkirk said on 14/08/2018:
Thermashield have just completed replacing windows and fitting patio doors for us. The service was top quality from start to finish.  Ronnie made 3 visits before my wife finally decided what she wanted and he was happy to give her the time she needed to make the right choice.  The 2 fitters were professional and courteous and did a top-quality job.  I can’t recommend this company highly enough.  If anyone wants to see the work they’ve done for us then contact Lynn and she’ll put you in touch with us.  Very happy customers.

Kenneth Miller, Falkirk said on 30/05/2018:
Had a non pushy salesman, with no pressure.  Replaced windows, to a new style.  Workmen were polite, efficient and informative, did a great job, clean and tidy as they went.  Even hoovered up!!  Took all rubbish away and left site tidier. Would certainly recommend them.

Alasdair Graham, Stenhousemuir said on 27/04/2018:
Replacement fittings and windows for porch, excellent service, very professional and excellent quality. Would happily recommend them to other potential users

Mary Connolly, Glasgow said on 23/04/2018:
Just had Ronnie back to fit new bathroom window.  Excellent service as usual. Have used him several times. Always the price he quotes and always on time and great quality.  Offers very good advice and would highly recommend his company for any work you may be considering.

Mrs Buchan, Polmont said on 10/04/2018:
Contacted Ronnie when we needed a replacement back door for our garage, and he arranged a suitable time to visit, came on time and gave us advice on type of door, measured up for the replacement upvc door and gave us a quote, he said how long it take to be made and he would phone to arrange the fitting.   The joiner arrived to fit the door on time as arranged, and did a very professional job as well as cleaning up and taking our old door away. I would be happy to use this company again in the future and would recommend to anyone.

Mrs C McCabe, Cumbernauld said on 29/03/2018:
First class service from Ronnie and his men from providing a reasonable quote to completing the installation of 9 new windows in our home. Great workmanship.

Lynn Hunter, Grangemouth said on 14/03/2018:
I’d arranged for a main window to be replaced at one of our tenancies. Ronnie & his team provided an excellent service from start to finish and the completed job looks great! Very good value for money and a great service. Thanks Ronnie.

A McArthur, Camelon said on 07/03/2018:
Excellent service from start to finish, and you don’t pay until work is completed, not a lot of company’s do that, and my windows are first class, would definitely recommend.

Sandra MacKay, Grangemouth said on 20/01/2018:
I contacted Ronnie of Thermashield to estimate double glazing for my window and door.  Work carried out by his two tradesmen who were very efficient, quick, they cleared mess then hoovered.  Next day Ronnie returned after work done, after ensuring that all was ok with work done and that I was pleased with everything.  He gave me invoice as estimated, reasonable total, all persons were very pleasant and I would certainly recommend them to everyone needing this work done.

Sean Atkinson, Dunfermline said on 22/12/2017:
Fitted a new back door. Price was very good and the company was very polite, punctual and professional. They even fixed a window that needed adjusted that they had not fitted and did not charge me. A1 service that I would definitely recommend.

Murray said on 01/12/2017:
Had Thermashield fit some double glazed windows. They were excellent, would definitely recommend.

R McCullagh said on 30/11/2017:
We’ve had windows replaced and new windows installed by Thermashield Windows & Maintenance Ltd. I imagined this work would be full of problems: cost over-runs, delays, dirt, collateral damage, etc. None of this happened. The first meeting to select products and measure up was really easy. Everything from then was straightforward, quick, well-done and very tidy. Big investments can be a real worry but Thermashield did the work so well that we have had no cause to regret.

J Todd, Stenhousemuir said on 16/10/2017:
Thermashield recently replaced a door and a couple of windows for me. The service was excellent from the great advice from Ronnie at the outset through to all aspects of the installation. Would definitely recommend.

Scott Taylor, Dunblane said on 28/07/2017:
Recently phoned Thermashield about a new composite front door. Ronnie visited and went through the options available. Door is now, fitted and couldn’t be happier with the end result. Would definitely recommend.

Katy Macfarlane, Stirling said on 28/07/2017:
I am so pleased with our new door. The service has been great from start to finish. Great advice on door styles and prompt service. Would highly recommend.

Lynn Hunter, Grangemouth said on 18/07/2017:
When I needed to replace my front door I contacted Ronnie and his team as they are fairly new to Trustys and I wanted to try them. I honestly can’t fault them in any way. The job was done meticulously. They turned up on time and tidied up completely after. No damage done to surrounds either so no need to decorate. Happy days. I’ve no hesitation in recommending Thermashield.

Ms Margaret Parish, Cumbernauld said on 10/07/2017:
Installed a very large window/sliding door into our conservatory. The workmen were very professional and did a wonderful job. They were clean, tidy and polite . I would definitely recommend them.

Customer, Linlithgow said on 09/07/2017:
We have been supplied with windows and doors on three separate occasions during the last two years. This firm has been a pleasure to work with, great product, helpful, on time and very very tidy with odd problem resolved without fuss. Happy to continue to do business.

Ian McDonald, Glasgow said on 13/06/2017:
We got replacement windows installed in our house and the company and the window fitters were very professional in the way that they conducted themselves, from getting the quote until the windows were installed.  The men installing the windows were very clean and tidy and respected our home. I would gladly recommend this company .

Joe and Isobel McAbery said on 06/06/2017:
Our high quality and reasonably priced French doors were supplied and fitted by Ronnie and his
From initial enquiry to completion their helpfulness, courtesy and efficiency were outstanding.
We are pleased to recommend Thermashield.

L Doherty, Cumbernauld said on 25/05/2017:
Thermashield have replaced double glazing for me recently. They were efficient and job was completed quickly.

Gillian MN, Edinburgh said:
We used Thermashield to replace brown wooden windows with statement grey double glazing. So happy with the result. Ronnie and the team were friendly, efficient, TIDY (yes tidy) and kept us informed throughout the quote, ordering and installation phases. Really competitive quote and we’ll be using them again for replacing our front door and oversized hall windows. Excellent company and really happy to recommend.

Dr & Mrs McAllister, Cumbernauld said:
Thermashield have just completed the replacement of 4 double glazed windows. This is the 3rd time that they have done work for us. Each time, they arrive at the time arranged. The workmen are friendly, efficient and professional. The work was carried out to a high standard. They cleaned up well after themselves. Ronnie checks up to ensure that everything is up to standard. There is never any high pressure sales nonsense. Ronnie gave us a very reasonable quote. We would recommend Thermashield to anyone who is seeking a high standard product, supplied and professionally fitted for a reasonable price.

Ross Martin, Morland & Martin Plumbing & Heating said:
I’ve known Ronnie for years. He is completely honest and I have no hesitation recommending him for Trustys.

Scott Gray, The Vital Spark said:
I highly recommend Ronnie and his team

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