Dunelm Gel Fusion Memory Foam Mattress Topper reviewed

The Dunelm Gel Fusion Memory Foam Mattress Topper is a gel-infused memory foam layer, sold in 6cm and 10cm depths, that softens a mattress which feels too firm. It is one of Dunelm’s most reviewed toppers, with an average of 4.5 stars from 901 customer ratings on its Dunelm product page at the time of writing (September 2026).

Construction and care

The foam carries gel particles and has ventilation holes punched through it, both meant to carry heat away from the body. It sits in a removable quilted cover whose top face is 40% viscose and 60% polyester, with an underside of 83% polyester and 17% cotton. Dunelm lists the cover as machine washable and safe to tumble dry on a low heat, and elastic straps at the corners, visible in Dunelm’s product photos, hold the topper on the mattress.

The foam is CertiPUR approved. Under the CertiPUR programme run by EUROPUR, certified foam is made without heavy metals such as mercury, lead and cadmium, emits low levels of volatile organic compounds, and is re-tested every year while the three-year label is valid. Dunelm still warns of a slight odour on unpacking and advises airing the topper for 24 hours before use.

Prices by size and depth

Dunelm sells the same four UK sizes in each depth. These are Dunelm’s regular prices, checked on 28 September 2026, when the 6cm double was out of stock online.

How it feels and who it suits

We rate the Gel Fusion medium-soft, 4 out of 10, and Dunelm itself notes that the feel depends on the mattress underneath. The 6cm depth takes the edge off a firm mattress. The 10cm depth changes the feel far more and suits side sleepers who need cushioning at the shoulder and hip.

An independent reviewer backs the cooling claim. Rachel Tompkins slept on the 6cm double for two weeks for Ideal Home, during a spell with daytime temperatures of 25 degrees, and wrote that she “didn’t wake up feeling sweaty and clammy like I often do”. She also reported a strong off-gassing smell for the first few days and said she could feel the ridges of the foam through the cover and sheet.

Limits

There is no sleep trial. Dunelm’s returns policy allows a change-of-mind return within 28 days only for unused items in their original packaging, so the Gel Fusion has to be right first time. On a mattress that is already sagging, a topper makes little difference, and a new mattress is the better spend. Gel and vent holes reduce the warmth of a dense foam layer without removing it, so very hot sleepers may still prefer a fibre or wool topper.