February in a UK rental flat usually means one thing: The Cold.
You are sitting on the sofa in a jumper, watching your smart meter tick up, feeling a literal breeze coming through the closed window.
If you have single glazing or old sash windows, you are essentially trying to heat the street.
You can’t force your landlord to upgrade to double glazing. But you can hack it.
The solution? Secondary Glazing Film.
This is a transparent sheet that you stick to the window frame. You blast it with a hairdryer, it shrinks tight like a drum skin, and it creates a sealed air pocket. It effectively turns single glazing into double glazing for about £10.
We paired this with the best draft excluders for warped frames and gaps under doors to create the ultimate “Heat Saver Kit” for renters.
Comparison: The Warmth Warriors
| Spec | Best for Glass tesa Moll Thermo Cover | tesa Moll E-Profile | Vellure Door Draft Stopper |
|---|---|---|---|
| Best For | Glass Insulation | Window Frame Gaps | Front/Bedroom Doors |
| Tech | Heat-Shrink Film | EPDM Rubber | Self-Adhesive Strip |
| Install Time | 15 Minutes | 5 Minutes | 2 Minutes |
| Removable? | ✅ Yes (Hairdryer) | ✅ Yes (Peel off) | ✅ Yes (Velcro) |
| Renter Rating |
The Physics of “Dead Air”
Before you buy, you need to understand how this works.
Insulation works by trapping still air.
The Film: Creates a pocket of air between the cold glass and your warm room. This stops the cold glass from sucking the heat out of the air.
The Rubber Strips: Stop the physical movement of air (drafts) whistling through the cracks in old wooden frames.
1. Top Pick: tesa Moll Thermo Cover (The Film)
This is the famous “Hairdryer Hack.” tesa is the German adhesive giant, and their Thermo Cover is the industry standard.
Why It’s Renter Friendly
- Invisible: Once you shrink it, it becomes crystal clear. You genuinely cannot tell it is there unless you touch it. Your landlord won’t notice it during an inspection.
- Condensation Killer: Because the warm air in your room can’t touch the freezing cold glass, it stops condensation forming. This is a massive weapon against Black Mould.
Pros:
- proven to reduce heat loss by up to 30% on single glazing.
- Stops condensation pooling on the windowsill.
- Easy to remove (just peel the tape off).
Cons:
- Installation Skill: It takes patience. If you rush it, you get wrinkles.
- One Season Only: You usually take it down in summer to open the windows, and you can’t reuse the film next winter.
2. The Gap Filler: tesa Moll E-Profile (Rubber Strip)
If you hold your hand near the edge of your window frame and feel a breeze, you need this.
The E-Profile is a self-adhesive rubber strip shaped like an “E”.
Why It’s Renter Friendly
- Compression: Unlike foam (which goes flat after a week), this EPDM rubber bounces back. When you close the window, it squashes down to seal the gap. When you open it, it springs back.
- Durability: It is rated to last 8 years. It won’t crumble or rot like cheap foam strips.
Pros:
- Stops the “Whistling wind” noise instantly.
- Self-adhesive backing is extremely strong.
- Brown or White options to match your frame.
Cons:
If your gaps are tiny (<1mm), this might be too thick and stop the window closing easily.
3. The Door Guard: Vellure Premium Draft Excluder
Old rental doors often have a huge gap at the bottom. You are paying to heat the hallway.
The Vellure is a heavy-duty strip that sticks to the bottom of the door and brushes along the floor.
Why It’s Renter Friendly
- The “Velcro” System: Unlike cheap ones that glue directly to the door, Vellure uses a Velcro strip. You can take the excluder off to clean it without ripping the paint off the door.
- Carpet Friendly: It uses a smooth material that glides over carpets without snagging or getting stuck.
Pros:
- #1 Bestseller for a reason.
- Blocks noise and smells (cooking/hallway) as well as drafts.
- Can be cut to size with scissors.
Cons:
- It is visible (unlike the window film).
Annotated Manual: The “Hairdryer” Technique
Installing the tesa Thermo Cover is easy, but tightening it is the magic part. Most people panic when they stick it up and it looks baggy.
Step 1: The “Double Sided” Frame
Clean your window frame with alcohol (essential!). Stick the double-sided tape all the way around the frame. Peel the backing.
Step 2: The “Baggy” Stick
Stick the film to the top tape first. Then pull it down to the bottom. Then sides.
Don’t worry if it looks wrinkly. Just ensure there are no gaps in the seal.
Step 3: The Heat Shrink
Turn your hairdryer to Hot / High.
Hold it 5cm away from the film. Move it back and forth over the wrinkles.
- The Magic: You will see the wrinkles vanish instantly as the plastic tightens. Keep going until it rings like a drum when you flick it.
Real-World Reality: Community Feedback
We checked DIYUK and MoneySavingExpert to find the installation pitfalls.
MAINTENANCE
1. “The Paint Peal”
USER REPORT
“I ripped the tape off in Spring and it took the paint off the window frame”.
💡
The Smart Tenant Fix
The tesa tape is strong.
Our Advice
Just like the Cable Trunking guide, do NOT rip it off cold. Use a hairdryer to warm the tape before you peel it off. This melts the glue and saves the paint.
MAINTENANCE
2. “The Condensation Trap”
USER REPORT
“I installed it, but now there is water trapped inside the film”.
💡
The Smart Tenant Fix
You trapped moist air inside.
Our Advice
You must install this on a Dry Day. If you install it just after a shower or boiling a kettle, you trap humidity. Wipe the glass perfectly dry before applying the film. If water gets in, you have to pierce a tiny hole to let it out (which ruins the insulation).
Frequently Asked Questions
Can I open the window with the film on?
No. The film seals the entire frame shut. You cannot open the window without breaking the seal. Only apply it to windows you don’t need to open in winter (e.g., the top sash or the bedroom window). Or, leave one small window unsealed for ventilation.
Will it damage uPVC frames?
No. It is safest on uPVC (plastic). The adhesive comes off uPVC very easily with a bit of WD-40 or Goo Gone. It is riskier on painted wood (use the hairdryer trick).
Does it really save money?
Yes. Energy Saving Trust estimates secondary glazing can save £15-£20 per year per window. But more importantly, it allows you to turn the thermostat down by 1 degree because you don’t feel the cold draft on your neck.
Verdict: Which One Do You Need?
- For Single Glazing: tesa Thermo Cover. It is the single most effective thing you can buy for under £10. It stops the cold radiating off the glass.
- For Drafty Frames: tesa E-Profile. If you can feel a breeze, fill the gap with rubber.
- For Cold Hallways: Vellure Door Excluder. Stop heating the communal corridor.