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The idea of central AC/Heat to me is so dumb. I much prefer the style of having individual units in individual areas. There’s no single point of failure, if you

by dimmke 3y ago

The idea of central AC/Heat to me is so dumb. I much prefer the style of having individual units in individual areas. There’s no single point of failure, if you only want one room to be extra cool it’s easy and faster to do. With central AC you have to set the temperature for the whole house and wait I’m sure there are reasons it’s so common that I don’t know about, it’s not even close to an area of expertise for me. But moving from the US to Mexico I feel like concrete is the way to go vs drywall and wood framing. Sound insulation is so much better too.

tdehnel 3y ago
It’s more expensive up front to have separate units for all rooms.
philwelch 3y ago
The rationale for central HVAC is that your house is insulated. If you heat or cool a specific room, heat is going to flow from one room to another and you’re going to have to keep fighting that. Getting the whole house to a specific temperature is more efficient since it’s insulated from the outside and can more easily maintain a set temperature with less work from the HVAC system. In older houses it didn’t matter as much because the insulation was shitty enough that this didn’t really work, but with modern insulation it makes more sense.
- dimmke 3y ago
  Yeah but everything I hear is that new builds in the US are worse than ever in terms of quality. I owned a brick ranch house in the US and had to have all the ductwork redone because it had accumulated mold. Cost me 3k. It just seems way more trouble than it’s worth.
  - philwelch 3y ago
    > Yeah but everything I hear is that new builds in the US are worse than ever in terms of quality. That's a meme. There's a lot of variability between houses (and the shitty old houses don't tend to survive long), but insulation is one of the things that has unambiguously improved over time. Matt Risinger has a good video on the "old houses were better" thing here, but his channel is full of great house-building content: https://www.youtube.com/watch?v=KBMMDY3LFAA https://www.youtube.com/watch?v=KBMMDY3LFAA
    - dimmke 3y ago
      I can only speak anecdotally, the house I owned was built in the 50s, so it makes sense that insulation wasn't as good. But my parents' house was built in the 80s, and has always had serious problems with the upper level being much hotter than the lower level. Apartments have never been as much of an issue, but they're usually much smaller and I've generally only lived in 1 bedrooms or studios. From what I have read, builds in the last 3 years have been horrendous due to supply and labor shortages. Maybe the sweet spot is to purchase something from before that era that is still new and get it thoroughly inspected. I still appreciate the improved efficacy I get from individual units. But maybe I've just never lived in a properly that has good central AC. I will watch the video, thanks for the link.
      - pengaru 3y ago
        > But my parents' house was built in the 80s, and has always had serious problems with the upper level being much hotter than the lower level. Sounds similar to my parents', which was built in the 70s, in IL. <story time> Last summer I visited and ended up doing a bunch of deferred home maintenance on the place. One thing I discovered was that the central air return vents weren't installed correctly, after 50 years of them paying out the nose for unnecessarily high electricity bills every summer. The construction technique used was clearly prioritizing low-cost and had the main return duct running the length of the house above the basement ceiling just opening up on top into the floor joists to reach rooms upstairs. The bays between the floor joists served as ducts branching out horizontally from above the main duct, and holes were cut in the upstairs subfloor where the stud bays in walls would serve as return ducts on the vertical axis. When they hung the main duct they left a huge gap separating the thing from the joists, upwards of two inches wide towards the far end from the air handler which was also beneath the vertical branch for reaching the highest/largest (and hottest) return vent upstairs. So despite having all these return circuits ostensibly present upstairs, the main return duct just pulled most of its air through this much closer and substantial gap drawing air from the lower level between the basement ceiling and the upper floor's joists. Everyone had always assumed the cold downstairs was expected because Basement, and that the upstairs was just always hot in summer because of poor insulation and all the windows. The way I identified the issue was by grabbing a long grocery store receipt and placing it across all the return vents while the AC was running (just get the blower on 100%). The receipt was nearly sucked through the basement return vent, and immediately fell off all of the upstairs return vents except the one directly above the air handler in the master bedroom. The one upstairs that worked doesn't depend on the long, leaky return duct. Then I fully blocked the obviously working return vents with cardboard, just to see if the non-working ones would start drawing enough to at least hold up the receipt - they didn't, zero change. I was able to improve the situation with a can of expanding foam filling the gaps on the main return duct, through drop-ceiling access... If I visit again I'm ripping out the basement ceiling to fix it properly. TL;DR: If you've got a house w/central air that seems to not cool specific regions, get yourself a piece of thin paper like a shopping receipt and some cardboard and try some process of elimination to verify the return vents are all sucking air. Don't just focus on output vents blowing cold. You can do this preliminary check without any tools or creating a mess, fixing what you find might be a different story though. </story time>
xeromal 3y ago
HVAC is much more efficient.

by dimmke 3y ago

tdehnel 3y ago

It’s more expensive up front to have separate units for all rooms.

philwelch 3y ago

The rationale for central HVAC is that your house is insulated. If you heat or cool a specific room, heat is going to flow from one room to another and you’re going to have to keep fighting that. Getting the whole house to a specific temperature is more efficient since it’s insulated from the outside and can more easily maintain a set temperature with less work from the HVAC system. In older houses it didn’t matter as much because the insulation was shitty enough that this didn’t really work, but with modern insulation it makes more sense.

dimmke 3y ago
Yeah but everything I hear is that new builds in the US are worse than ever in terms of quality. I owned a brick ranch house in the US and had to have all the ductwork redone because it had accumulated mold. Cost me 3k. It just seems way more trouble than it’s worth.
- philwelch 3y ago
  > Yeah but everything I hear is that new builds in the US are worse than ever in terms of quality. That's a meme. There's a lot of variability between houses (and the shitty old houses don't tend to survive long), but insulation is one of the things that has unambiguously improved over time. Matt Risinger has a good video on the "old houses were better" thing here, but his channel is full of great house-building content: https://www.youtube.com/watch?v=KBMMDY3LFAA https://www.youtube.com/watch?v=KBMMDY3LFAA
  - dimmke 3y ago
    I can only speak anecdotally, the house I owned was built in the 50s, so it makes sense that insulation wasn't as good. But my parents' house was built in the 80s, and has always had serious problems with the upper level being much hotter than the lower level. Apartments have never been as much of an issue, but they're usually much smaller and I've generally only lived in 1 bedrooms or studios. From what I have read, builds in the last 3 years have been horrendous due to supply and labor shortages. Maybe the sweet spot is to purchase something from before that era that is still new and get it thoroughly inspected. I still appreciate the improved efficacy I get from individual units. But maybe I've just never lived in a properly that has good central AC. I will watch the video, thanks for the link.
    - pengaru 3y ago
      > But my parents' house was built in the 80s, and has always had serious problems with the upper level being much hotter than the lower level. Sounds similar to my parents', which was built in the 70s, in IL. <story time> Last summer I visited and ended up doing a bunch of deferred home maintenance on the place. One thing I discovered was that the central air return vents weren't installed correctly, after 50 years of them paying out the nose for unnecessarily high electricity bills every summer. The construction technique used was clearly prioritizing low-cost and had the main return duct running the length of the house above the basement ceiling just opening up on top into the floor joists to reach rooms upstairs. The bays between the floor joists served as ducts branching out horizontally from above the main duct, and holes were cut in the upstairs subfloor where the stud bays in walls would serve as return ducts on the vertical axis. When they hung the main duct they left a huge gap separating the thing from the joists, upwards of two inches wide towards the far end from the air handler which was also beneath the vertical branch for reaching the highest/largest (and hottest) return vent upstairs. So despite having all these return circuits ostensibly present upstairs, the main return duct just pulled most of its air through this much closer and substantial gap drawing air from the lower level between the basement ceiling and the upper floor's joists. Everyone had always assumed the cold downstairs was expected because Basement, and that the upstairs was just always hot in summer because of poor insulation and all the windows. The way I identified the issue was by grabbing a long grocery store receipt and placing it across all the return vents while the AC was running (just get the blower on 100%). The receipt was nearly sucked through the basement return vent, and immediately fell off all of the upstairs return vents except the one directly above the air handler in the master bedroom. The one upstairs that worked doesn't depend on the long, leaky return duct. Then I fully blocked the obviously working return vents with cardboard, just to see if the non-working ones would start drawing enough to at least hold up the receipt - they didn't, zero change. I was able to improve the situation with a can of expanding foam filling the gaps on the main return duct, through drop-ceiling access... If I visit again I'm ripping out the basement ceiling to fix it properly. TL;DR: If you've got a house w/central air that seems to not cool specific regions, get yourself a piece of thin paper like a shopping receipt and some cardboard and try some process of elimination to verify the return vents are all sucking air. Don't just focus on output vents blowing cold. You can do this preliminary check without any tools or creating a mess, fixing what you find might be a different story though. </story time>

xeromal 3y ago

HVAC is much more efficient.