Which are the best blinds for cold insulation

During the deep cold spell on 2022, I was advising customers on which blinds are the best for covering windows during the cold and with helps for everyday purposes as well.

There are a lot of options to cover your windows currently, and most customers have an idea of what they would like in their windows.

When a cold spell comes, this is an additional question that customers need answering, but first we need to go over what blinds do to the windows to insulate the room, this will help us understand why certain blinds work more than others, and why blinds have an advantage over curtains

How do blinds insulate the room

First we must understand what is happening to better understand what blinds do to insulate the rooms.

When it is cold outside, the windows are the coldest place in the room, the cold crawling its way in quicker through the thin window panes, when you start to feel this, the heating goes on and you have a fight at the windows between the heat inside and the cold outside the window.

This creates a convection effect, this is when the cold of the window cools the air in the room, which then slows the warm air and lowers that now cold air, drawing in new warmer air, which the cold outside air again begins to cools and starts a repeating effect, this starts a draft, this is a movement of air caused by the difference in warm air in the room (or on the beech) and cold air outside (or of the sea which is why the sea is always windy).

Now we understanding the convection effect a bit, we can now start to understand why we should cover our windows for more than privacy.

How do Blinds or window covers help

With the understanding over the convection effect (link right here if you want to learn more) keeps your rooms colder than the room should be, what should you use to cover your windows?

The idea is to add an extra layer between the rooms heat and the windows cold that permeates into the room, this provides and insulation gap, most new builds have a cavity wall, this is to allow circulation and a protection between the internal elements and external elements, making the building more energy efficient.

This applies with double glazing, the problem with double glazing is that windows are still very cold to start with and thin, with, glass being a translucent material, means it is designed to let “light” in and add a separating layer without having a dark room!

Adding the cover of blinds or curtains to stop the cold air (convection) entering the room, gives us a thicker layer to protect the heat in our room, blinds and curtains are a great way to save money on our heating bills and keeping our rooms warmer for longer.

What is best for covering your Windows

Lets start with curtains for context

Curtains

This curtain was fitted in Swansea, a new build, this curtain isn’t thermally lined, getting a thermally lined curtain or thicker materialled curtains helps, although anything that adds a layer between your room and the windows is a plus, the curtain is covering a long window adding a “wall” between the window and the heat, slow the the two circulating, thus adding to the room temperature and stopping the room thermostat engaging more often (like a buying a car with more miles per gallon)

The downsides are old houses and some new are built with radiators under the windows, and for good reason, but when a curtain is fitted over the window and above the radiator (sometimes over the radiator as well) most of the heat escapes behind the curtain and the heat is interacting with the cold window instead of the room, this is what makes blinds better (more on this below)

Another downside is the fact the gaps at the top allows the cold to mix with the warm air at celling level, thus drawing heat into the window space, the bigger the window, the worse this problem is.

Before we start, nothing is technically bad, just degrees of better and you need a blind for more reasons than protection from the cold.

Vertical Blinds

Here are two pictures to explain Verticals and how they help, as you can see the first photo is similar to the curtains photo above.

You can see the difference right away, the curtain COVERS the areas, the Vertical Blind FITS in the area, this fitting in the area adds a better wall layer of protection between your room and the window, the blind being closer means there is less permeation of the cold into your room, these verticals above are not blackout, but with blackout blinds, less cold and heat will mix.

the photo of the two verticals, one in the window and one in the door instantly shows how Vertical blinds benefit over curtains, with the radiator just under the window, and the drapes of the curtains passing the top of the radiator, this means heat will rise behind the curtains and mixing with the cold window before heating the room, now with the vertical blind in the window, this will stop a majority of the mixing and more heat will enter and heat the room.

The down sides of verticals is the amount of gaps between the slats, and how easily disturbed the stats are, due to the nature of verticals, they hang their, weighted into place, but will move with the slightest of breezes, heat fortunately rises, and the slats are over lapping in a vertical fashion which helps keep the cold and heat mixing.

Venetian Blinds

Above are two pictures of venetians, one Faux wood venetians, the second is Perfect fit venetians

Venetians are a step up from verticals in my option, thicker and sturdier in weight, less likely to move, and will hold in the heat, providing a solid Wall of plastic or wood when shut, to keep the heat in the house.

Similar to verticals the slats over lap, and when the heat touches the slats, the slats being thinker takes more cold to penetrate the layer and trying to cool the room, if the slats are tilted away from the room, with the face of the slat pointing out towards the window, this will stop the heat getting through the string gap and interacting with the cold window.

this string gap, and the way the slats face effects the ability to be the top blind for keeping your room warm, this is offset by the thinness and sturdiness of the blinds and a mindfulness to till the face of the blinds to face outside will massively improve your rooms heat.

Perfect fits are a category of their own, the most popular are the venetian type, so we wont discuss the other options, similar problems as the above counter parts, but with the versatility of being in the actually window space this closes the ability for the cold to enter the room, although thinner and metal, this is a plus and minus.

Roller blinds

This is an interesting one, the large sheet area adds a solid fabric wall that covers the recess keeping the room, made of similar fabric to vertical blinds, the lack of gaps put roller blinds higher for protection against the cold (if this is the main reason you are buying blinds)

The picture above is in a bayed area, heat mainly stays in the upper part of the room. which shows how the roller blind would help keep more heat in the room over verticals, a solid fabric that adds a removable wall against your room and your windows, adding great insulation.

The only downside is the control wheel gaps at each side, these gaps can be from 1cm to 3cm wide, this is a lot of gap and it comes down to the obstacles that the roller blind needs to pass.

Roman blinds

Here is two sets of Roman Blinds to show why I rate these the top blind to insulate your windows.

First is the fabric, thick curtain style fabric, with added thermo-lining, makes roman blinds a lot warmer for your room to start with.

Roman blinds have a warm feel also, made from similar curtain material, hold a lot of warm air in the material, feeling warm and providing warmth.

The second reason is how close they are to the wall, the purple Roman Blinds above shows this, compared to curtains, you have no ruffles, the Roman blind lies against the wall and adds a lovely flush cover, keeping your rooms heat and the cold separate.

When the roman blind is in the recess, there is hardly any gaps on the sides of the blind, this keep the cold and heat mix to the bare minimum giving you a close cut finish that no other blind can match.

I hope this long thread helps, but the winner in my opinion is ROMAN BLINDS for heat insulation