$9 Harbor Freight Mat Keeps Your Bed Warm With No Heat, No Gas, No Electricity — It Goes UNDER You

Summary

Elias Mercer argues that waking with a cold back or hips may be caused by heat escaping into the mattress—not just by cold air above the bed. Blankets trap still air when they’re above you, he says, but compress under your weight. A layer of closed-cell foam beneath the areas bearing most of your weight can help reduce heat loss. It won’t heat the room or raise the thermometer reading.

Key Strategies and Tips

• Check both sides of the bed: Compare the layers over you with what’s beneath you. If there’s only a thin sheet under your body, Mercer suggests addressing that “bottom” layer.
• Use closed-cell foam under your body:
  • Look for foam labeled closed-cell or EVA; avoid memory foam or egg-crate foam for this purpose.
  • Mercer describes a Harbor Freight anti-fatigue mat as a low-cost option. He recommends placing it under the shoulders, back, and hips rather than covering the whole mattress.
  • If the mat is thin, fold it double beneath the shoulders and hips.
• Layer the bed in this order: Bare mattress → foam mat → old blanket or folded quilt to soften the feel → flat sheet → usual blankets.
  • Let a rolled mat lie flat before using it, and trim it to fit if needed.
  • Mercer advises using a flat sheet rather than a fitted sheet, which may not fit over the added layers. Tuck it securely at the foot and one side, leaving the other side loose for getting out of bed.
  • If the bed feels too firm or your hips or shoulders are uncomfortable, add a thicker quilt between the mat and sheet.
• Try a temporary option for tonight: Use a yoga mat, several flattened cardboard boxes, or a folded wool blanket. Mercer cautions that cardboard doesn’t tolerate dampness and won’t last. He also mentions interlocking foam floor squares.
• Set expectations: The mat does not generate heat, and the room thermometer should stay about the same. It may reduce heat loss at the bed’s surface. Mercer says it may matter less on a thick foam mattress and more on an air mattress, cot, thin mattress, or bed on the floor.
• Avoid common mistakes: Don’t put the foam mat on top of you, where it duplicates the role of blankets. Mercer says a reflective emergency blanket belongs over you or beneath the mat—not directly under your body.
• Use safe heating practices: Never use candles, tea lights, grills, or charcoal to heat a bedroom. Use a flashlight, and keep generators outside, at least 20 feet from the house.
• Know when bedding isn’t enough: Mercer warns that a mat is not sufficient if the home remains very cold. He urges viewers concerned about an older adult to watch for symptoms such as confusion, sleepiness, slurred speech, persistent shivering, or clumsiness, and to call for help. He suggests contacting 211 to find a warming center and deciding in advance when to seek one.

Presenters and Sources Mentioned

• Presenter: Elias Mercer
• Amos: Mercer’s relative, whose journal and advice he recounts
• Sources cited by Mercer: Texas state health department; National Institute on Aging; outdoor campers and an outdoor writer
• Retailers and products mentioned: Harbor Freight, Walmart, Ace Hardware, Target; Harbor Freight anti-fatigue mat and foam floor squares