Should we put in AC

[s/v Jedi]

Originally Posted by SV Confianza

That's...a lot. When we looked at options, we considered these (from the traditional, non vsd type) and pitted their stats agains the VSDs

Webasto FCF Platinum - 16k btu - 1288W
Dometic Marine Air EnviroComfort 16000 - 1208W
Marinaire MSBA16k2 - 16k btu - 1242W

Surely that is without the pump! For the one I posted about, the unit takes 750W and the pump 50W.

My March pump is 250W.

[SV Confianza]

Originally Posted by s/v Jedi

Surely that is without the pump! For the one I posted about, the unit takes 750W and the pump 50W.

My March pump is 250W.

I *think* I included the pumps, but I’d have to double check. The MarinAire pump is only 20 Watts, so it’s negligible. Just double checked on their site.

[FlyingScot]

We have two Marbru 12k btu/hr units and I'm happy we do. Sometimes you just need to cool the space down to get any work done. Sure, like anything it can be over done.

Ours use under 600w each all in. We rarely use both at the same time. Being 12v there is also no load on the inverters, which allow the inveter(s) to be off or running other things. You won't need as much inverter capacity.

Our old Dometic 16k btu/hr units used 1300w each with the water pump.

Power is everything and efficiency matters. Yes you have to pay way more for 30-40% efficiency improvement. I hope they last a long time.

There will always be people who say you don't need (insert every single item on you boat, sans hull). Regarding the story about the wife who doesn't leave the boat, well, at least he is living his dream. She's doing what she wants. I bet without AC they wouldn't have a boat at all.

Others on here can't seem to contemplate that things vary in efficiency. The modern inverter based split systems used around the world are also very efficient and much cheaper if your boat design allows for installation of such types. It is a fact that turning your compressor speed down increases the efficiency. Heck, even your simple fan is likely more efficient at lower speeds.

[FlyingScot]

Originally Posted by SV Confianza

I *think* I included the pumps, but I’d have to double check. The MarinAire pump is only 20 Watts, so it’s negligible. Just double checked on their site.

Please share what 500GPH pump uses 20watts.

[NYSail]

We love our ac units……. We always anchor and yes there is typically a nice breeze, especially at night. But then there are the days / weeks that are sweltering and the boat gets and stays real clammy. Nothing ever dries. There is Nothing better than switching on the ac units when we get back to the boat….. make some hot water for a showers after a full day exploring, dry and cool down the boat while cooking a great dinner, then turning them off and going to sleep. The boat stays cool and dry through the night.

And then there is the early spring and fall…… we typically launch in April and stay out on the boat through November….. heat in the NE is nice!

Really depends where you are and your tolerance to heat or cold.

Oh and btw…… this is all possible due to our genset that I installed a couple of years ago as we have given up our slip and never plug in.

However it is all a big expense…… for over 15 years on my other boats (cal 34 mk III and Pearson 36-2) we did not have air conditioners (nor the space or the money) and felt great with any weather just because we loved staying on the boat and knew no different……. We were younger too. Ha

Good luck on your decision and with the circumnavigation! Great boat btw….

Greg
s/v Souleil

[SV Confianza]

Originally Posted by FlyingScot

Please share what 500GPH pump uses 20watts.

Apologies for the late response. The specs are here for the pump: https://www.marinaire.com/pump-p/mfp500kt.htm

[SV Confianza]

Originally Posted by FlyingScot

We have two Marbru 12k btu/hr units and I'm happy we do. Sometimes you just need to cool the space down to get any work done. Sure, like anything it can be over done.

Ours use under 600w each all in. We rarely use both at the same time. Being 12v there is also no load on the inverters, which allow the inveter(s) to be off or running other things. You won't need as much inverter capacity.

Our old Dometic 16k btu/hr units used 1300w each with the water pump.

Power is everything and efficiency matters. Yes you have to pay way more for 30-40% efficiency improvement. I hope they last a long time.

There will always be people who say you don't need (insert every single item on you boat, sans hull). Regarding the story about the wife who doesn't leave the boat, well, at least he is living his dream. She's doing what she wants. I bet without AC they wouldn't have a boat at all.

Others on here can't seem to contemplate that things vary in efficiency. The modern inverter based split systems used around the world are also very efficient and much cheaper if your boat design allows for installation of such types. It is a fact that turning your compressor speed down increases the efficiency. Heck, even your simple fan is likely more efficient at lower speeds.

You're totally right the Mabru's seem to be the kings of efficiency. If you scaled up their power consumption to 16k btu (assuming it's linear), then you're only talking 800 watts, vs 1200 for other contenders (and then add inverter losses...).

Wish they made a 16k btu unit. Justifying the cost would be a tough pill to swallow, but it would be nice to run the A/C more often (with the power savings) and keep the boat dry.

The issue that I still have with the marketing of VSDs is that there's not much transparency. They should tell us what we should expect in kWs per *day* given different conditions.

From my understanding, sure, you might get up to a 15% efficiency savings (according to coastal climate control) in a compressor by running it at lower speeds, but that's only within a very specific range. It actually gets *worse* if you run it slower than that range (example: https://america.sullair.com/en/blog/...drive-oil-free).

So, I'm sure you can design a compressor with the exact correct size that it sits in that range only. But are the manufacturers doing that?

Add to that, if the compressor is running longer, so is the pump, so that eats away some of the potential efficiency.

We only have a standard for household A/Cs, but you can see by the SEER ratings, that they're don't really beat out the higher end traditional A/Cs.

I *want* more efficient A/C and refrigeration so that we can all have access to creature comforts off our solar. I just don't like the thought of fellow cruisers paying 2-3x the price for marketing claims if some units aren't actually providing real benefit.

All that said. Mabru's 12kbtu efficiency is super impressive. I hope they make bigger units in the future. Although, I wonder if that's the optimal range of their design. The 5k btu units aren't even close to as efficient based on their specs.

[malbert73]

FWIW when our home HVAC was replaced last year from a standard carrier unit whose compressor cycled on and off to a new inverter style Bosch HVAC that ramps down compressor speed, we really noticed only a small amount of energy savings. Not disappointed as I would have gotten it anyway as it’s quieter, but I do think there’s more marketing and hype than actual major energy savings.

[Sailorichiban]

Hello All,
Different strokes for different folks.
That said, my recollections of screens ,scoops , 12 volt fans in every compartment, extreme temperature and humidity left only one choice; to do what was necessary to make AC functional.
In fact, during one cruise reversed course and headed north to cooler climes due to non operational generator, hence no AC.
Vicious blood sucking insects combined with high temperatures and humidity, pretty much require AC with no alternatives.
Lots of experience with tropical climates, can be positively unhealthy without reasonable Aircon, not to mention the difficulties of reducing molds in such an environment.
Each to their own, but I believe the choice is obvious.
Best of luck to all!

[ekelly36]

For the cost of one of the marine 12V AC's you can buy 5-6 minisplit systems. There are DC and AC systems for 400-600 bucks all day on amazon that pull a max of 1600 watts or less depending on how much cooling you need. Throw a soft start on and some decent battery cap... easier and alot cheaper to replace once it bites the dust...