inverter

When using DC machinery in RV has lot of advantages, replacing the equipment you already have, when you need inverter anyway might not make economical sense.
I do have one of those $19 300W inverters for cars and the cheap fan can be really squeaky.
Than the 1600W Xantrek makes less noise, but for long stay the fan takes lot of power.
There is no "one size fits all" for most of the users and I would consider 2 inverters for motorhome.
If CPAP takes less than 120W, you can buy fanless inverter that will make no noise at all. Just observe cooling space.
Than for microwave get one of those 1000W and don't worry about noise.
Inverter/charger would be top of the line, so would be replacing motorhome with Prevost conversion that will have all the electrical already set.
Your choice

Also of note, if you do go to 120v inverter, is what sine wave requirements for the CPAP. Does it require PSW or is MSW good enough?

Mowermech Thanks for the update. How many batteries do you have and do you use the Humidifier? The 12VDC power cord seams like the way to go. I had no idea the C-pap would run on DC. I have 4 batteries in my coach so there should be no problem.Thanks

Why have 1000 watts if 300 will do the deed? Overhead from running the 1000 watt may be higher. Morningstar is the "go to" inverter in the 300 watt size.

DW and I both have CPAP machines by Phillips.
Both are 12VDC machines, with 110VAC adapters. I bought the 12VDC power cords for both machines, and we run both of them all night on the coach batteries no problem.
In fact, when we have electric hookups, we still use the 12VDC power cords.
There is no inverter in our coach. We have never missed it.

I also run a 300 wat for my CPAP. What I found is to place the inverter as close to the battery and then run the 110 power cord back to the CPAP. Ac runs a longer run without loss then DC

I had a Magnum 2000 watt which the RV place said was bad, but I sent it in to Magnum and they fixed it under warranty. 2 year warranty gets extended to 5 years if you have a control panel.

The RV shop replaced it with an MSW Xantrex 2000 (after chasing down the bad ground that I told them was the actual problem). Both were mounted in the basement compartment that has the transfer switch and Progressive surge protector. Can't really here it.

At a thousand watts you will find they all have noisy fans... You might consider mounting near the battery - you will save on the heavy guage wire for the 12v connection and it will be out of the living area... Then run regular 10g house wiring to a detacated plug with a remote switch

Here is a nice model that comes with a nice remote/monitor included
http://www.invertersupply.com/index.php?main_page=product_info&cPath=390_405&products_id=2158

You might spend a little more for a 2,000w version - Here is a nice setup:
http://youtu.be/gm4NeZCQyvY

Our coach came with the Xantrex 458 Freedom 2000 watt inverter/charger that is a MSW inverter and when we installed the RR frig we installed the Magnum 2812 PSW inverter. One reason the wife likes to sew and machine motors do not like MSW, also electric blanket may also catch fire and it may also be hard on C-Pap machines machines and pc.
JR

My 300 watt Go Power sine wave is very quiet.
Fan only comes on near full load.

+1 for Morningstar that is absolutely silent with no fan.