1.5 TOG Sleep Sack Temperature: The Range Brands Agree On

We checked eleven baby sleep sack brands. Five of them publish a room-temperature range in Fahrenheit for a 1.5 TOG, and across those five, the only band they all share is 68–72°F (20–22°C).

Outside that window, they split: the widest runs 64–75°F (18–24°C), the narrowest 68–73°F (20–23°C). That shared band sits inside the range Kaiya Baby publishes for 1.0 TOG. Three of the eleven, including Kaiya Baby, never added a 1.5 step at all.

What temperature is a 1.5 TOG sleep sack for?

All five put a 1.5 TOG sleep sack in a room holding 68–72°F (20–22°C).

That figure comes from stacking the five published ranges on top of each other and taking the part they share: the highest lower bound (68°F / 20°C) to the lowest upper bound (72°F / 22°C). Each of the five agrees a 1.5 TOG belongs somewhere in that band.

None of them agrees on what happens on either side of it. If you want the whole scale rather than this one step, we keep a room temperature chart for choosing TOG.

Two conditions attach to that number. These are brand-published figures, not an industry standard. TOG measures thermal resistance, and no standards body assigns a room temperature to a TOG value.

They are also not medical guidance. Treat them the way you would treat a clothing size chart: a starting point that still needs checking against your own room.

Outside 68–72°F (20–22°C), the five ranges pull apart by up to 4°F (2.2°C), so the full spread is worth seeing.

How much do published 1.5 TOG ranges differ?

Here are five of the eleven that publish a 1.5 TOG range in Fahrenheit, captured 16 September 2026. Two more publish in Celsius for the UK market and appear further down.

Brands publish these in different units, so both are given throughout: Fahrenheit as published by the US brands, Celsius as published by the UK ones, converted where a brand states only one.

The widest range is 11°F (6.1°C), the narrowest 5°F (2.8°C), so one brand's 1.5 TOG covers more than twice the temperature span of another's.

The mechanism behind the spread becomes clear once you know what TOG measures. TOG rates the fabric's thermal resistance and nothing else. The room temperature printed alongside it is each brand's own addition, and it carries an assumption about what the baby is wearing underneath.

A brand assuming a short-sleeve bodysuit underneath has to place the same sack in a warmer room to reach the same result, so it prints a warmer range. A brand assuming a long-sleeve sleepsuit prints a cooler one.

Same sack, same TOG, different published range. Fabric choice moves the same needle, and how sleep sack fabrics differ sets out the comparison.

One caveat on the table: Momcozy's guide gives 68–73°F (20–23°C) in its FAQ and 70–74°F (21–23°C) a few paragraphs earlier in the same article. We have listed the FAQ figure and flagged the conflict rather than picking one silently.

1.0 vs 1.5 TOG: which one does your room need?

The 68–72°F (20–22°C) band those five brands share falls inside the range Kaiya Baby publishes for a 1.0 TOG sleep sack.

Kaiya Baby publishes 1.0 TOG as 68–75°F (20–24°C). The consensus 1.5 TOG band starts at the same 68°F (20°C) and stops three Fahrenheit degrees (1.7°C) lower.

For a room sitting anywhere in that shared window, a 1.0 TOG and a 1.5 TOG are both inside their stated range, and the choice between them comes down to what you layer underneath rather than to the sack itself.

Competitors say this out loud. Love to Dream's UK guide notes that a 22°C room falls in both its 1.0 TOG range (20–24°C) and its 1.5 TOG range (18–22°C), and that either will work.

The condition worth holding onto: 68°F (20°C) is where the answer actually changes. Below it, you are out of the 1.0 range and into cooler-room territory, and that is a real reason to move up rather than a preference.

For a nursery holding 68–75°F (20–24°C), that is the band to shop, and our full 1.0 TOG guide takes that step on its own.

Which brands do not publish a temperature at all?

Two of the eleven sell a 1.5 TOG sleep sack with no room-temperature range anywhere on the product page.

Mori lists a 1.5 TOG sleeping bag on both its US and UK stores, and Perlimpinpin sells a 1.5 TOG collection. All three pages name the rating repeatedly and state no room temperature anywhere on the page.

This is a gap in the information, not a judgment about the products. A stated range is what lets you line a 1.5 TOG up against the 1.0 and 2.5 either side of it.

Without one, the only thing left to compare the three by is how each feels in the hand, and thickness is a poor proxy for thermal resistance across different fabrics.

Why do some brands skip 1.5 TOG?

Three brands in this review skip the 1.5 step: ergoPouch, Tommee Tippee, and Kaiya Baby.

All three run a four-step ladder instead. Kaiya Baby's is:

Those four steps run from 3.5 TOG sleep sacks at the cold end to 0.5 TOG sleep sacks at the warm end, cover 57°F (14°C) to 80°F (27°C) without a gap, and meet at 68°F (20°C).

A 1.5 TOG sits on that seam. Its consensus band, 68–72°F (20–22°C), is the bottom 4°F (2.2°C) of the 7°F-wide (3.9°C) 1.0 step. The colder end HALO and Love to Dream reach down to, 64–68°F (18–20°C), is the top 4°F (2.2°C) of the 7°F-wide (3.9°C) 2.5 step.

The condition where a 1.5 earns its place: a room that holds steady around 66–68°F (19–20°C) year-round, close enough to the seam that neither neighboring step feels right. That is also the honest limit of any multi-season claim made for a single weight: it holds where the room holds, not across a whole year of rooms.

For rooms that move with the seasons, the four steps cover the same ground with one fewer purchase. Once the reading sits below 68°F (20°C), our 2.5 TOG sleep sacks are the step built for it.

Which season is a 1.5 TOG for?

By its published range, a 1.5 TOG is a spring and autumn weight, not a winter or summer one.

Is 1.5 TOG warm enough for winter?

By the band all five US brands agree on, only if the room holds at 68°F (20°C) or above overnight; HALO and Love to Dream rate their own 1.5 TOG down to 64°F (18°C). Kaiya Baby labels 61–68°F (16–20°C) as the band for cool nurseries and winter nights.

Three of the five published 1.5 TOG ranges start below 68°F (20°C) and so reach into the top of that band (HALO and Love to Dream at 64°F (18°C), Quince at 66°F (19°C)), and none of the five reaches its 61°F (16°C) floor. If your reading lands in that band, a 2.5 TOG is the step built for it.

Is 1.5 TOG OK for summer?

Only at the cooler end. Kaiya Baby labels 75–80°F (24–27°C) as the band for warm rooms and summer nights, and 75°F (24°C) is exactly where the highest published 1.5 range, HALO's 64–75°F (18–24°C), stops. Above that reading, you are past every 1.5 range in the table, and a 0.5 TOG is the step for it.

The condition that overrides all of this: season and room temperature are not the same thing. A well-insulated apartment in January and a drafty bedroom in May can land on the same reading. Use the thermometer in the room, not the month on the calendar.

How do UK charts treat 1.5 TOG?

In the UK, a 1.5 TOG is published in Celsius and lands on a different part of the year.

Love to Dream's UK guide gives 1.5 TOG as 18–22°C, and BabyGo gives 18–21°C. Both reach about two degrees lower at the cold end than the US consensus of 68–72°F (20–22°C).

BabyGo also treats 2.5 TOG as a year-round default rather than a winter step, because 2.5 TOG is the weight aimed at the room temperature British health guidance names.

The NHS tells parents to keep a baby's room between 16C and 20C, and the Lullaby Trust gives the same 16–20°C range.

Those are UK sources, and the TOG-to-temperature convention itself comes out of the UK. Neither transfers automatically to a US nursery.

The American Academy of Pediatrics safe sleep guidance sets out how a baby should sleep without naming a room temperature at all, so there is no equivalent US number to quote. The ranges in this article are brand figures throughout and are labeled as such.

One practical consequence: a 1.5 TOG is shopped as a spring weight in Britain and an autumn weight in the United States. Search demand for it in the UK peaks in May; in the US it peaks between October and December.

What should a baby wear under a 1.5 TOG sleep sack?

Only two of the eleven publish what to put under a 1.5 TOG sleep sack, and they do not land in the same place.

Quince pairs a 68–70°F (20–21°C) room with a short-sleeve bodysuit or lightweight footed pajamas. Love to Dream's UK chart, working in Celsius, pairs 1.5 TOG with a babygrow and sleeveless bodysuit at 20°C and short-sleeve, long-leg pajamas at 22°C.

Our own ClimaCuddle bodysuit is made in long sleeve as well as short, so the layer underneath can follow those charts without the sack changing.

The reason layering matters this much is the same reason the brand ranges disagree. TOG rates the sack alone. Everything underneath adds thermal resistance that the rating does not account for, so a long-sleeve sleepsuit under a 1.5 TOG produces a warmer setup than the range on the label describes.

That is why the layer underneath, not the TOG number alone, decides how warm the setup ends up. For the full breakdown by temperature, see what to put under a sleep sack.

Whatever you choose, read the result on the baby rather than trusting the label alone. Our guide to too hot or too cold covers which signals to trust and which ones mislead.

What if your room sits between two TOGs?

None of the eleven publishes a rule for a nursery that sits between two TOG steps, so here is the one we use: measure across several nights and pick the step that contains the lowest reading, not the average.

A room that is not held at a set temperature drifts down overnight, so an average describes a temperature the sack only meets for part of the night. Sizing to the low point leaves you one lighter layer to remove on milder nights. Sizing to the average leaves nothing to add when the room bottoms out.

If the reading lands near 68°F (20°C), either neighboring step will work and the layer underneath decides it. If it sits clearly above or below, take the step that contains it. Style matters alongside warmth, and the Kaiya Baby sleep sack selection guide walks through sleeves, feet, and fit.