Liner or heavyweight: which keeps my horse warmer?

The University of Maine's blanketing bulletin defines grams as the polyfill insulation inside the fabric and says the higher the gram count, the heavier the insulation. It lists a quilted liner at 100 to 300 grams, a lightweight turnout at 60 to 100 and a heavyweight at 300 and up. Heavyweights start at 300 grams in the Rutgers and Horseware guides too.

So the arithmetic is simple. Our medium weight page notes that a 220g turnout over a 100g liner gives about 320 grams of fill, inside the heavyweight band. Our lightweight page says a 100g turnout over a 100g liner gives about 200 grams, a mediumweight's warmth, and a 300g liner takes it to 400.

Treat those sums as estimates. Horseware's guide, as our Horseware blanket guide describes it, says the gram number on a label is the fill over the back, where it is thickest, and some blankets carry less lower down. Fit and wind matter too. The totals tell you what range you are in; your horse's skin tells you whether it worked.

That is how our heavyweight turnout blankets page puts it: a heavyweight goes on in the fall and stays on, while a liner system adds or removes 100 to 300 grams without a second outer.

A heavyweight also suits the horses that get cold first. The same page lists seniors, clipped horses, hard keepers and horses new to the cold. A senior grows less coat, a clipped horse has lost his insulation and a hard keeper burns feed to stay warm.

The tradeoff is the afternoon. A heavyweight left on through a mild day can leave him sweating, which is why our too hot or too cold page says to check again after the warmest part of the day. If he sweats in a heavyweight, drop to a mediumweight.

Our heavyweight page says a light shell with liners suits that kind of weather, and our lightweight page says a lightweight turnout with liners covers more of the winter than one blanket alone, buying a mediumweight instead if the cold settles in for weeks.

They also keep one outer shell on the horse through the whole season. You swap warmth, not the waterproof layer, and you do not need a full second blanket for a handful of cold nights. For that case, our heavyweight page suggests a medium shell with one liner, or a neck cover, rather than a heavyweight you will wear a few times.

The bigger point is flexibility. One rider on our heavyweight page runs a 100g outer with 100g and 300g liners, and says that handles most weather. That is one rider's setup, not a rule.

Our medium weight page says to check that the liner attaches to your outer at the neck and the leg straps, and to size it to match the turnout. Horseware's liners, as our Horseware guide describes them, come in 50g, 100g, 200g and 400g, with pony and extra-large sizes, and attach with Velcro loops at the neck and clips at the back.

Liners and stable sheets are not meant to get wet. The University of Maine bulletin says so directly. A liner is warmth, not weather protection, so it lives under a waterproof outer. If a liner does get soaked, take it out and dry it.

The Horseware guide also says its liners go in a home washing machine, which is handy at season's end. Check the care label on whatever you buy, and see our wash and reproof page for the outer.

Our heavyweight page says a medium shell with one liner or a neck cover handles a handful of nights, and our neck covers page says a neck cover earns its place when the body stays warm but the neck and crest take the wind and rain. It describes clipped horses, seniors and horses living out without shelter as the usual cases.

Decide by where the weather hits him, not the calendar: a neck that stays damp while his body is comfortable is the sign. Style matters. A detachable neck clips on and comes off on milder days, a combo neck is sewn on and stays put, and a full hood runs up to the poll. Check how it fastens before you buy, and check the mane and withers for rubbing after the first few days.

The University of Maine chart calls for that combination below 0°F for a full-coated horse and below 15°F for a clipped one. So even the heavyweight camp ends up layering when it gets that cold, and our neck covers and hoods page covers the hood.

For the mid-range, the same chart puts a full-coated horse in a heavyweight from 0 to 14°F, a light or midweight at 15 to 24°F and no blanket (a rain sheet if it is raining) at 25 to 39°F. A clipped horse moves up each step: a heavyweight at 15 to 24°F and a light or midweight at 25 to 39°F.

Those are one bulletin's lines, written for Maine. Wind, rain, age and where your horse grew up all move them, as we show on the blanket weight page. Use the chart as a starting point and then check your horse.

Static is a liner-fabric complaint, and riders have strong opinions about which kind is best. We have no published test comparing liner fabrics, so take these as individual experiences rather than a ruling.

On the staff point, the rider quoted above chose a heavyweight because other people make the changes. If you board, ask who switches blankets, how often, and whether they can manage a liner. A simple temperature to switch to a heavier blanket is easier to follow than a liner schedule. If you do the changes yourself, you have more room to layer.

Our medium weight page says to pick the weight for your coldest typical week, then add a liner or a second blanket for the rest. Liners come in a range of weights; Horseware's, as our Horseware guide describes them, run from 50g to 400g, so you can take a small step or a big one.

Think about what the outer is. A lightweight shell can take a larger liner to reach heavyweight territory, and a medium shell needs only a small one. Sizing: our heavyweight page quotes a rider who runs liners of the same size as the outer, which is the point of matching. Check how it attaches at the neck and leg straps before you commit, as our medium weight page says.

If you are not sure how many layers you will really change, start with the outer and one liner, and see how the winter goes. Our blanket selector and blanket weight calculator can narrow the starting weight.

The grams can match either way. These are the points our pages and the extension bulletin give:

• A heavyweight if he lives out through months of deep cold, or boards where staff change blankets.
• A light shell with liners if the weather swings through several ranges in a week and you make the changes.
• A medium shell with one liner, or a neck cover, if hard cold comes only a few nights a year.
• Heavyweight, liner and hood together if you face the coldest range on the University of Maine chart.
• Whichever you pick, check the skin at the shoulder and withers, and adjust.