Ask Lemmy

So you have three options, I'm going to break them down just because I think comparing all three is helpful for long term planning, but skip to the end for advice on a specific window unit.

1. Upgrading your central AC and/ or it's duct work.

• Cons:
  • 💰 Expensive - central units are expensive
  • 🧑‍🔬 Installation - these require professional installation from certified technicians.
  • 🪚 Duct work - if it requires duct work changes then modifying the house to accomodate is a whole nother headache.
• Pros:
  • 😸 Efficiency / long term electricity savings - a newer central AC will be more efficient for cooling the whole house down. They typically have SEER ratings in the 15-18 range.
  • 🔇 Noise - you might hear them start up, but most rooms of the house hear nothing from the vents.
  • ☀️ Light - they don't impact natural window light at all
  • 🌡️Heat Pump - newer units are typically heat pumps that can efficiently and economically heat your house in the winter or at least shoulder seasons.

2. Getting a window unit.

• Cons:
  • 🌥️ Light Reduction - Blocks some of the window
  • 😿 Efficiency - Typically* lower efficiency ratings
  • 🔊 Noise - You'll inherently have more noise from a fan blowing cold air into the room (compared to a central vent), and because the outdoor compressor unit is so close, most window units* also have quite a lot of sound coming from the outdoor portion.
  • 🥶 AC Only - Typically no heat pump capabilities.
• Pros:
  • 🫰Cheap - Lowest up front cost
  • 👨‍🔧 Easy installation - DIY
  • ↪️ Portability - Can be removed or sold later if it's not needed.
  • 😸Efficiency? - while central AC units are typically more efficient on a per unit of cooling basis, if your window AC is in the right room it can actually be more efficient overall. i.e. if it's in your bedroom, even if the window unit is less efficient than a central one, you might use less electricity just cooling your bedroom and letting the rest of the house get warmer.

3. Mini - Split Systems - install a compressor outside your house and a blower unit in a specific room or hallway

• Cons

  • 💲💲Expensive - these are more expensive than window units up front by quite a bit.

  • 🙇/👩‍🔧 Installation - Potential DIY - while they do sell DIY mini-split systems that don't require professional installation, you'll be limited by the length of pipe / hoses they provide, so need a suitable spot for your compressor unit. Otherwise you'll need a pro to install it.

  • 🔉Noise - since the compressor is outside and separated by a wall you shouldn't hear it if it's mounted properly, but you do still have an indoor blower unit. It'll be quieter than a window unit but louder than a vent.

• Pros
  • ☀️ Light - no light blocking
  • 🐸 Efficiency - Mini splits often have efficiency ratings that meet or exceed central units, on top of the fact that they can be used to just cool the needed room.
  • 🌡️Heat Pump - these are also typically heat pumps.

If it were me personally, and I owned the house, and I was worried about cooling my bedroom, and I had the money and somewhere to mount the compressor, I would buy a DIY mini split system. I will always want my bedroom to be cold for sleeping and the rest of the house doesn't need to be that cold (and vice versa in winter since they're heat pumps that go both ways). The only real downsides are the very light fan noise from the blower unit, and the upfront cost, though that can potentially be mitigated if you live in a jurisdiction that offers some type of home retrofit or heat pump grant (worth checking!).

That being said there's a bunch of caveats and criteria there that I personally didn't meet, so I bought one of those Midea U shaped units that everyone talks about and am honestly very happy. There was a massive recall recently, but they're adding drains to fix the issue, and these units otherwise are way better than most other window units, though they only work with windows that slide up and down vertically.

*But unlike most other window ACs, the U shaped units have the window sit between the outdoor unit and the indoor unit which blocks most of the noise from the compressor, lets more natural light come in, and doesn't require blocking the sides. They're also very efficient with a CEER rating of 15.

Even despite the recall they're still what I'd personally recommend, you might be able to find one second hand.

Also note that I don't consider a portable air conditioner an option. They're terrible.