Hi Sedge,
Welcome to the forum. As an Irishman now living in the US I can understand your frustrations, and having lived in Dublin for a year myself, doubly so! I know many are saying you have to think differently etc but having lived both, it is far easier here. Having moved from Ireland to the USA in 2011, my eyes have been opened by the shear opportunity here to increase ones net worth by living simply, something that really wasn't an easy option back home. I would have moved here years earlier if I had known.
Income: I will say your income is impressive for Ireland, well done. When I left Ireland my salary was €35k as an engineer with a few years experience, that almost doubled moving to the US and with that still I consider myself under payed in US terms for my experience (the joys of my former H1B visa indentured servitude!). Engineers are paid far more handsomely in the US than at home. You're earnings are definitely on the high end of things in Ireland, similar to many on this site being on the high end of US incomes, the median household income over here is around $52k I believe.
Housing: I am living in the Midwest so definitely a LCOL area in the US but then I moved from Galway which is not as expensive as Dublin. I can confirm that housing agenerally is cheaper here, mortgage rates are lower and can be fixed for their entire duration which is impossible back home. When I left Ireland in 2011, I was renting a two bed ground floor apartment for €750 (25% of my income at the time so your statement holds true) in a reasonable but not high end area (students and young professionals), it was the cheapest 2 bed apartment I could find at the time. I am now paying $650 mortgage on a 3bed 2200sqft ranch house with a 3 car garage on half an acre. There is no comparison. Looking at
www.daft.ie the cheapest 2bed house in Dublin to rent is €1k and as you likely know, many areas in Dublin are less than desirable for a family. I am thankful to have lived with an uncle in Rathgar when I was there, he bought back in the 1980s, I can only imagine what that place is worth now. Unfortunately the Dublin house prices have remained pretty firm and increased, most of the bust was felt in prices in the rest of the country.
Childcare / Education: I cant comment on this one really as I don't have kids yet but my wife is an Elementary school teacher and generally there seems to be better services for afterschool / latch key, buses home etc in the US. It has been many years since I attended my rural primary school but looking back it would have been difficult for any family with two working adults. When I worked in Dublin in 2006 one of the women in the office quit her job after her third child as she saved more in childcare than she earned working. My wife worked as an afterschool teacher in a creche in Galway when we lived there, I remember the cost being pretty expensive. Cost of education provided seems similar in both until it comes to University where you will have a big advantage in Ireland in that tuition is free, hopefully it remains so (although im not sure if its free even on your income?). Student Loan debt here is insane and such a terrible way to start out in adult life.
General: In general I find day to day things are cheaper here in the US, Petrol/Gas is far cheaper here in the US, food is a little less (eating out is far cheaper), clothes are cheaper although I don't buy much (my wife misses Penneys though), Electronics and consumer items are cheaper.
Things I found more expensive are used cars (weirdly new cars are less expensive here), appliances (although it think its because they are bigger), The furniture aspect of renting is more expensive to start as most places are unfurnished whereas Ireland they are furnished. Things like Gas, Electric, Water and Waste are probably similar but location dependent, A/C ups our electric here in Kansas during the summer.
Travel is more expensive here (no Ryanair to use!) but with travel hacking / points if you are responsible, then it is cheaper here in the US (less exotic mind!).
Obviously healthcare is more expensive here in the US, although it can depend on age and condition I guess (I actually pay similar to what I did back home if I don't have any visits outside of preventative care in a year). Dental costs are similar to home, UK is cheapest on this one. As a side note, I saw the 2016 budget brought in free GP care to all children under 12, that's nice.
Taxes: Income taxes are lower in the US but then we have property taxes on our houses which I didn't have in Ireland. Car Tax is dependent on state but I can almost 100% say it is less than Ireland (Car insurance is similar).
Savings / Investments: This is where the US has the
MAJOR advantage, the amount of pre-tax and low cost investment vehicles available here in the US is unbelievable. In Ireland these pre-tax options are non existent other than traditional pension buckets, the UK is not much better but is slightly (worked in Belfast for 4 years). Take me and my wife here in the US for example, we have a 401k ($18k limit), 403b ($18k), 457 ($18k), TIRA ($11k), her KPERS (6%) and my HSA ($3350) as pre tax investment accounts available to us for a total of about $70500 pre-tax investment space. This lowers our net / taxable income to about $40k, with a few deductions we will end up paying about $2500 in federal tax on $110,000 income, if we had kids we would likely pay no tax.
In Ireland for your €100k you are paying 28% on taxes, PRSI, Levies etc (not sure if you have included a pension in there) whereas on $110k here in the US we are paying about 11% on Fed & State Taxes, Social Security & Medicare.
Thats a big difference right there - 17%, simply by using pre-tax accounts and lower taxes in general Advice for people living in the USA, DON'T MOVE ABROAD BEFORE REACHING NET WORTH TARGET!
This is my plan, reach net worth target here in the US (likely 10 years or so) and retire to Ireland (or Northern Ireland / UK as my wife can teach there without the Irish language and doesn't really care about FIRE, yet anyway, 10 more years of teaching and we'll see!)
I don't consider us living a frugal existence by any means and when we do have kids we can / will scale back in quite a few departments while still maintaining a comfortable lifestyle. We can save over 60% of our income pretax and plan to squeeze out some more over the coming years for investment properties.
I personally think you are doing well for someone living in Dublin with a family, maybe investigate some alternatives on childcare, housing perhaps look at further out in one of the commuter towns as that may have two fold advantage of lower housing and lower childcare costs (but then public transport, traffic and commute hours will be issues as our road network in Ireland can be frustratingly congested and inefficient)
Sorry for the long response, I hope it is somewhat helpful.
Sean Og