Consumer's curtain investigation; how to keep warm this winter

Honeycomb blinds, pictured, came out tops in Consumer NZ's testing on which curtains and blinds will keep you warm this winter. Image / Consumer NZ

Keeping your home this winter doesn't have to put you in debt, but you will have to be creative.

Consumer have revealed the best curtains to invest in as temperatures begin to cool down to help stop nearly two-thirds of a home's heat from going out its windows.

Honeycomb blinds - which have hexagonal shaped cells in its structure - were the standout performer of the five different blinds tested. Others involved were roman, roller and aluminium and wooden venetians.

Both thermal and heavy-lined curtains were also tested.

Consumer head of testing Dr Paul Smith said the heat loss test was measured through an aluminium-framed single-glazed window with each curtain hung for at least three hours.

He was pleased to find the honeycomb blinds topped the test having put them in his own home about nine years ago.

He said the hexagonal cells in the curtain, which when extended trap the air in the cells, "acting like a down jacket; trapping still air".

"It was good for me seeing this because anecdotally I thought 'oh these are doing a great job' because when you open the curtains in the morning you can see all the cold air fall out from behind the window."

In the test, the honeycomb blinds retained more than 60 per cent of the heat lost through a bare window.

Roman blinds were the second best performing blind, followed by roller blinds.

As for wooden or aluminium venetians, wooden were proven the better insulator, he said.

If curtains were preferred, people were urged to go "heavy" and long.

Heavy-lined curtains were ones which had two layers which again acted as an air trap. To get the best result, they needed to go down to the ground, no matter the size of the window, to keep the cold air out.

It was best to keep the gap between the curtain or blind and the frame of the window as small as possible.

Thermal curtains - a curtain which has a thermal layer stitched to the back - did not perform as well as the heavy-lined curtains, he said.

However, Dr Smith had come up with a few cheap hacks for people not bothered about what there lounge or particular room looks like for a few cold nights over winter.

One was hanging a blanket over the top of your curtains.

"It is less convenient because you've got to hang a blanket and take it down each time.

"We pinned it up where the railing was, so we just pinned it up above the window and just let it hang down and cover the whole window."

The other option was to roll up towels and sit them above your window railing which again prevented cold air circulating around the room.

"It stops the air being sucked in to the top. So when the hot air rises up to the ceiling. If the curtains aren't well-fitted, that warm air falls behind the window.

"They call it the reverse chimney so it's like the air coming down past the window and all the heat being lost, so if you put something across the top it stops that from happening."

TOP TIPS FOR HEAT RETENTION

• Mount curtains as close as possible to the window frame,
• Position nets as close to the window as possible,
• Use floor length curtains and ensure they touch the floor,
• Make curtains a generous width so they overlap the window frames at the sides,
• Using net curtains help with heat retention, especially on wooden frame windows,
• Using a fan "significantly" reduces heat loss.