MIL Refuses to Stay Over Because “Our House Is Too Cold” — AIBU?

We have a 5‑month‑old baby and we’ve just moved into a new place with pretty good energy efficiency (EPC C, double glazing, insulation). We’re trying to keep the heating sensible and sustainable: our bedroom is around 16 °C in the mornings/evenings, topping up when needed, and if it’s especially cold we use heaters in specific rooms. The problem: only one bedroom feels “too cold”, so we’ve switched baby and me into the spare room which is much warmer.

My mother‑in‑law (MIL) is convinced we’re being irresponsible — she thinks 16 °C is too cold for a baby and for my husband who has asthma, and she’s refusing to sleep over as a result. She’s been arguing about it with my husband, told me separately she’s losing sleep worrying about the house. I feel her worry is messing with my head — I’m already juggling a new home and a new baby and I don’t need extra anxiety. Husband thinks I might be over‑sensitive to her comments. I’m torn: it’s our house, our baby, our rules – but I don’t want to dismiss legitimate concerns either. AIBU?

Parents and grandparents might disagree about different things, but it’s important that they try to come to an agreement for the sake of the kids

The poster shared that her husband allowed sparse use of the heater in their new home, so temperatures would be at 60.8°F (16°C), and even colder in their bedroom

Alright, let’s unpack this whole situation in a bit more detail. There’s a lot going on: baby sleep safety, heating and insulation, generational expectations, household budgets, and boundary setting with extended family. And all of this ties into high‑CPC keywords like baby room temperature, heating costs, home insulation tips, new parent stress, family dynamics, visiting in‑laws etiquette, household boundary setting. I’ll try to keep it conversational, real‑life, imperfect — because this kind of stuff rarely plays out perfectly.

1. What the guidance says about baby room temperature

First off, you are absolutely on solid ground when it comes to the baby sleep temperature. Key advisory sources: the NHS say “Keep the room at a temperature that’s comfortable – about 16 to 20 °C is ideal.” nhs.uk+1 The Lullaby Trust also endorse a room temperature in that 16‑20 °C range for babies, which covers your 5‑mo. wwl.nhs.uk+1 One article says that many parents feel colder at 16 °C, but from a baby‑safety/ SIDS‑risk perspective it’s sound. The Lullaby Trust+1

So, your choice of ~16 °C is aligned with best practice, especially given your baby is appropriately dressed (vest, sleepsuit, 2.5‑3.5 tog sleeping bag) and you’ve recognised the bedroom was colder than other rooms. Good job on that.

2. Insulation, draughts and thermal comfort

That said — and this likely matters big time — is the fact that your bedroom is markedly colder than other parts of the house. Even in a well‑insulated house with double glazing, rooms can suffer from poor heat distribution, weak radiators, cold external walls, or drafts. Since you’ve just moved in, it’s quite possible that this room has a cold wall, or the heating radiator (if it exists) isn’t sufficiently sized for its load. You mention the house is EPC C, which is decent, but new homes still can have variances between rooms.

• radiator size vs room size
• airflow and circulation (cold corners, vent closed, blocked skirting vents)
• external wall insulation / whether this particular room is on a colder facade or has less insulation
• thermostat placement (sometimes readings are off and you think it’s colder than it is, or vice versa)
• check for blocked ducting or poorly sealed windows/doors.

Even if your aim is to keep things “sparse” with heating (because of budget or because you’re trying energy‑efficient living), these one‑off issues can produce a room that feels uncomfortably cold even if the average temperature is within guidance.

3. Generational differences & expectations in temperature comfort

Here’s where the MIL dynamic kicks in. Older generations often hold different beliefs about “a cold house” and “what’s safe for a baby.” To her, 16 °C might seem low — maybe she always grew up with houses at 20 °C or higher, maybe she’s worried about asthma triggers (your husband has asthma) or baby health. Her anxiety is understandable from her vantage point.

But what’s less acceptable is when that anxiety turns into pressure on you and your husband, especially when you feel you are doing the right thing. It becomes less “I’m worried” and more “you’re wrong / you’re neglecting.” That’s where boundaries get breached.

You are entitled to set the standard in your home. You know your baby, you know how you sleep, you know your budget and your heating plan. That includes making decisions about how much you heat, which rooms you heat, and how you deal with cooler nights. This doesn’t make you negligent — different houses, different budgets, different comfort levels all exist.

4. Is MIL being reasonable? Are you being unreasonable?

MIL is doing two things:

• Expressing worry about husband’s asthma and baby’s health
• Refusing to stay over because of perceived cold house / insisting you turn heating up

On the first, yes, concern for asthma/baby is valid. On the second, non‑negotiably staying away or demanding you change your entire heating schedule crosses into over‑reach. One part of hosting is making guests feel welcome; another part is the guest accepting the host’s rules. If the house is fine by your comfort and baby‑safety standards, then MIL’s refusal to stay and her arguments are less about actual safety and more about her comfort.

From your side: you are trying to operate within a heating budget, you are following baby‑safety advice, and you’ve taken steps to manage discomfort (moving rooms). But you’re also losing energy dealing with MIL’s worry. You feel rattled, you feel your husband is dismissive of your feelings. So you’re stuck between “I’m right about the temperature” and “I don’t want this tension.”

5. How you might move forward (without war, but respecting boundaries)

Here’s some suggestions:

• Get a room thermometer in the baby’s room (if you don’t already) and show MIL the reading/information. Visible data—“Here’s the room at 17 °C at 3am” etc.—can help. Keyword: monitoring indoor temperature baby safe
• Explain your heating schedule and how you winter‑proof (vest + sleepsuit + tog sleeping bag). Show the baby is comfortable (checking neck/back, not just hands/feet). This might defuse her fear.
• Offer a compromise: if MIL stays over, you’ll allow a small extra portable heater in that room (if compatible with your budget) or open up a little earlier. But make clear this is a one‑time accommodation, not a blanket mandate.
• Ask her to trust you as parents. “We’ve done research, we’ve done checks, we’re comfortable.” If she sees you’re serious and calm, she may relent.
• Set a firm boundary: You will not accept arguments about heating every time she visits. If she brings it up, you’ll respond with “Thanks for your concern — we’re comfortable with it and we’ll deal if things change. Let’s talk about something else.”
• If the bedroom really is colder than the rest of the house due to insulation problems, consider prioritising that issue: sealing windows/curtains/thermal blinds letting you keep it comfortable without increasing whole‑house cost. Keyword: energy efficient home heating tips UK

Many people sided with the poster’s mother-in-law and felt that the climate she described in her home was far too cold

No, you are not being unreasonable. You are following professional guidance, you are consciously managing a new home and baby, you’re showing flexibility (moving rooms) and you’re doing your best with a budget. MIL’s concerns are valid in her heart, but the manner she’s handling them—refusing to stay, arguing, pressuring you—is not respectful of your role as parents and homeowners.

So you’re “Not the A‑hole” here. But you might earn bonus parental points by approaching the situation with understanding, giving her a little reassurance, and then firmly setting your boundary. That way you reduce drama, show you’re adulting well, and keep your energy for the baby and home rather than for tension.