House size to buy

[firelight]

We are planning to buy our first (and probably long term) home. Family of 4(2 adults and 1 toddler, 1 baby with possible addition of one more in future). My husband wants to get 4 bed/2.5 bath (or 3 bath) and so far likes houses in the 2000-2600 sqft range with a minimum of two car garages and a large back yard for kids. I want something easily maintainable and easy to Airbnb (atleast a room) since we don't have much stuff (we are in a 2 bed 2 bath apartment and I'm decluttering) and I don't want to add much unless it's necessary. I'm aiming for a smaller house (1500-2000). My husband argues that kids will need more space as they grow and it's better to have a larger house for entertaining. But heating and cooling is more cost-effective with a smaller house.

Questions:
1) Do kids really need a big house? They are of opposite genders and share a room now.
2) How do we find out what the cost of doing additions and changes to a house would be (ballpark figure)? For example, in the houses we've seen so far I've always wanted to make structural changes to the family room/kitchen area. But we don't know how to price it to consider our total cost.
3) how much down payment is good to have? I was thinking of 20% down but a lot of people suggest 10% or less.
4) how to choose a real estate agent?

Please suggest any books/sites/blogs for a complete beginner like me.

[Little Aussie Battler]

There are so many variables here.

Are there parks / playgrounds nearby, and is it a safe area?  If so, then I don't think you need a big house or yard.

Do you live close to family? If not, extra space for frequent visitors may be a good (or bad) thing.

Renovation costs will vary wildly from location to location. Where do you live?  You may be able to get some high level estimates from a builder if you describe the work, but structural changes can often uncover other issues (bad wiring, water damage, etc) that will blow out the cost.  I think you will struggle to get good cost estimates unless you actually buy and arrange proper quotes.  If you don't have renovation experience I would also strongly consider just buying a house with a suitable floor plan (you can always do a cosmetic renovation later).

[2Cent]

1. Outdoor space doesn't cost anything in heating and cooling.
One thing to have that is really nice is kitchen space. Home cooking is a big saver.
At least try to have space for bikes and outdoor playing gear which takes up lots of space. Kids with small houses will be in the street or park. That is not that good as you can not see who they are hanging out with (you will not be there when they are older). They will probably want their own room when they get to school age.
2. Ask a local contractor.
3. As little as possible with the current interest rates.
4. If you know the area, why would you need an agent at all?

[Tuskalusa]

Here are some thoughts.

We picked a neighborhood we liked and a price range. We wound up with a small house in a great, family friendly neighborhood.

Our son was 1 when we moved. As he got bigger, the house started to feel smaller. It was also hard to entertain in the winter months. Since we tend to entertain at home a lot, this became a challenge.

We planned to renovate said small house, but a bigger one went up for sale across 5he street. For the cost of a remodel, we moved.

If we could have afforded a slightly bigger house up front, in the neighborhood we loved, it would have saved some headaches. Our current home is 2600 SF. A little big...2000 would have been fine.

[YttriumNitrate]

For what it's worth, a little over a year ago I moved from a 1700 square foot house to a 4000+ square foot house, and my monthly gas/electric bills actually went down by about 15%. While the size of a house is one factor in determining how much you will spend on utilities, it is just one factor. In my case, the new house was by a lake and had tall trees nearby which have dramatically decreased the need for air conditioning in the summer. The old house was an odd L-shape while the new house has three stacked levels that are perfectly rectangular. The result is that the new house doesn't have that much more exterior surface area than the old house so the heating bills were about the same. Both houses have 95%+ efficiency gas furnaces. 

While my family certainly doesn't need a big house, I know my wife really appreciates it on rainy days when she is stuck inside the house with a two-year-old boy. I really appreciate having a big garage for storing my lake toys.

[MayDay]

Questions:
1) Do kids really need a big house? They are of opposite genders and share a room now.
2) How do we find out what the cost of doing additions and changes to a house would be (ballpark figure)? For example, in the houses we've seen so far I've always wanted to make structural changes to the family room/kitchen area. But we don't know how to price it to consider our total cost.
3) how much down payment is good to have? I was thinking of 20% down but a lot of people suggest 10% or less.
4) how to choose a real estate agent?

Please suggest any books/sites/blogs for a complete beginner like me.

We have two kids and had a ~2500 sq ft house briefly with 4/2.5.

It was a fucking lot of cleaning.

We currently have a 1600 sq ft 4 bedroom 1.5 bath house. Much smaller but laid out efficiently and feels about the second size in tes of functional space.

With 3 potential kids I would definitely consider 4 bedrooms unless the price is significantly higher. A lot of times the jump from 3 to 4 bedrooms be is a little ridiculous. But you don't need giant everything. 

We have had the absolute best luck with houses from the 50's-70's. And luckily that architecture and decor is back in style! Very usable spaces, efficient, but not tiny rooms with non-existent closets.

Kids do get bigger. Mine are 7 and 9. We paid 80k more to get the 4th bedroom but the real deciding factor was that the more expensive house had a basement family room that is usable for teenagers. The cheap house had 6' basement ceilings.

When we looked at additions it was ~200$ a sq ft for a simple addition with a basement but no plumbing.

[YoungGranny]

This wouldn't be MMM if someone didn't remind you all that a large house is LUXURY. You can choose to indulge in that luxury - my husband and I have a massive 1,600 sqft 3bd house with PLENTY of room for children down then road. I grew up in a 900sq ft 3 bedroom house as a family of 5 so to answer your questions:

1.) No kids do not NEED that much space - you may decide you WANT to give your kids their own space as they grow up but it's not necessary. Also, if you're in a region with basements an unfinished basement with some carpet thrown down is more than enough for any kid (that's what we got and we loved it). Plus, bigger rooms and play rooms just means more space to fill.
2.) It's hard to even ballpark that because it depends on the changes, if you're going to work yourself or outsource it, etc. I'm sure a google search would shed some light on average kitchen renovations, opening up floor plans etc.
3.) Depends on interest rates and PMI's. As interest rates start creeping up you should factor that + the pmi rate in to see what your interest rate is. It also somewhat depends on the person to me - if you're not putting 20% down as a strategy to invest more then great. However, if you have $X and you want to stretch it further and buy a bigger house then I say buy what you can afford with 20%.
4.) Our city occasionally has speed dating for realtors. It was a cool way to network and meet multiple agents. We picked one that is quick, responsive, friendly, and flexible. Everyone's different - i suggest meeting with a few and asking for recommendations from people you know.